Three-dimensional stacked nano-beam Pd-W18O49 material as well as preparation method and application thereof

Abstract

The invention discloses a three-dimensional stacked nano-beam Pd-W18O49 material and a preparation method and application thereof, and belongs to the technical field of functional materials.The method comprises the steps that cyclohexanol and acetone are evenly mixed, hexachloride is added, the mixture is evenly stirred, and W18O49 powder is obtained after hydrothermal reaction, washing and drying; and dissolving the W18O49 powder in a palladium acetate solution, carrying out a water bath reaction, washing again, and drying again to obtain the three-dimensional stacked nano-beam Pd-W18O49 material. The three-dimensional stacked nano-beam structure can provide a larger specific surface area and increase catalytic active sites; the ordered accumulation of the nano-beams is beneficial to the construction of a rapid electron transmission channel, and the electron conduction problem of the sulfur positive electrode is improved. Through the synergistic catalysis of rich oxygen vacancies and Pd and W18O49, the conversion reaction of sodium polysulfide is effectively accelerated, the shuttle effect is inhibited, and the charge-discharge efficiency, the cycle stability and the actual capacity of the battery are improved. A new breakthrough is brought to the performance improvement of the sodium-sulfur battery, and the practical application of the sodium-sulfur battery in the field of large-scale energy storage is promoted.

Description

Technical Field

[0001] This invention belongs to the field of functional materials technology, specifically relating to a three-dimensional stacked nanobundle Pd-W 18 O 49 Materials, their preparation methods, and applications. Background Technology

[0002] In the field of energy storage, sodium-sulfur batteries, with their high theoretical energy density (1274 Wh / kg) and abundant reserves of sodium and sulfur, have become highly promising candidates for large-scale energy storage applications. Among them, room-temperature sodium-sulfur batteries, compared with commercial high-temperature sodium-sulfur batteries that need to operate at 300°C, not only significantly reduce system costs but also avoid the safety hazards caused by high-temperature operation. Furthermore, because their discharge product is Na2S, they have a higher theoretical energy density, demonstrating enormous development potential.

[0003] However, the practical application of room-temperature sodium-sulfur batteries faces numerous challenges. The insulating properties of sulfur and the slow conversion kinetics of sodium polysulfides during charge and discharge lead to rapid capacity decay and insufficient cycle life. Particularly in the liquid-to-solid (Na₂S₄→Na₂S₂) and solid-to-solid (Na₂S₂→Na₂S) conversion stages, the sluggish kinetics make it difficult for the readily soluble polysulfides (NaPSs) generated at the positive electrode to be rapidly converted into insoluble Na₂S. This results in NaPSs dissolving in the electrolyte, passing through the separator, and directly contacting the metallic sodium negative electrode, triggering a "shuttle effect." This leads to irreversible loss of the sulfur positive electrode and a significant decrease in battery capacity.

[0004] To address these issues, developing efficient catalysts to accelerate the conversion of sodium polysulfides and suppress the "shuttle effect" has become a key research direction. Among numerous potential catalyst materials, transition metal oxides have attracted considerable attention due to their excellent chemical stability and unique electronic structure. Among these, non-stoichiometric monoclinic W... 18 O 49 Due to its abundant oxygen vacancies, it exhibits unique advantages in the field of catalysis. The presence of oxygen vacancies can alter the electronic state of materials, providing more active sites for catalytic reactions and promoting the adsorption and transformation of reactants. 18 O 49 Oxygen vacancies and low-valence tungsten (W) on the surface 4+ / W 5+ These sites are the core sites of catalytic activity, but they are easily oxidized or reconstructed during the reaction, leading to a decrease in the concentration of free electrons, a weakening of the SPR effect, and consequently a decrease in catalytic efficiency. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the present invention aims to provide a three-dimensional stacked nanobundle Pd-W 18 O 49Materials, their preparation methods, and applications are explored to address the technical problems of slow kinetics, shuttle effect, and sulfur insulation in existing sulfur batteries.

[0006] To achieve the above objectives, the present invention employs the following technical solution: This invention discloses a three-dimensional stacked nanobundle Pd-W 18 O 49 Methods for preparing materials include: Cyclohexanol and acetone were mixed thoroughly, then hexachloride was added and stirred until homogeneous. After hydrothermal reaction, washing, and drying, W was obtained. 18 O 49 Powder; W 18 O 49 The powder was dissolved in palladium acetate solution, reacted in a water bath, washed again, and dried again to obtain three-dimensional stacked nanobundles of Pd-W. 18 O 49 Material.

[0007] Preferably, the ratio of cyclohexanol, acetone and hexachloride is (10~20) mL: (40~50) mL: (0.003~0.005) mol.

[0008] Preferably, the stirring conditions are: stirring at room temperature for 5-15 minutes; the hydrothermal reaction conditions are: reaction at 150-180°C for 8-12 hours.

[0009] Preferably, the washing conditions are: washing with ethanol and water by vacuum filtration; the drying conditions are: vacuum drying at 60~80 ℃ for 15~30 min.

[0010] Preferably, the palladium acetate solution is prepared by dissolving palladium acetate in N,N dimethylformamide; the molar concentration of the palladium acetate solution is 0.5~0.8 mmol / L.

[0011] Preferably, W 18 O 49 When the powder is mixed with the palladium acetate solution, the ratio of Pd to W is as follows: 18 O 49 The mass ratio is (0.01~0.05):1 for mixing.

[0012] Preferably, the water bath reaction conditions are: stirring at a rate of 300-500 r / min, in a water bath at 50-60°C for 6-10 hours; The drying conditions are: vacuum drying at 60~80 ℃ for 15~30 min.

[0013] This invention discloses a three-dimensional stacked nanobundle Pd-W 18 O 49 The material used is the aforementioned three-dimensional stacked nanobundles Pd-W18 O 49 The material was prepared using a specific method.

[0014] Preferably, three-dimensional stacked nanobundles Pd-W 18 O 49 In the material, Pd nanoparticles and W 18 O 49 At the heterogeneous interface formed by the matrix, electrons from W 18 O 49 Oxygen defect sites in the matrix are transferred to Pd nanoparticles.

[0015] This invention also discloses the above-mentioned three-dimensional stacked nanobundles Pd-W 18 O 49 Three-dimensional stacked nanobundles Pd-W prepared by material preparation method 18 O 49 Application of the material in the preparation of catalysts for room temperature sodium-sulfur battery cathode materials.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses a three-dimensional stacked nanobundle Pd-W 18 O 49 The material preparation method involves constructing a three-dimensional stacked nanobundle structure of Pd-W 18 O 49 The composite material effectively solves the problems of sluggish polysulfide conversion kinetics and electron conduction barriers in sodium-sulfur batteries. Cyclohexanol and acetone are mixed, and then hexachloride is added. The reducing properties of cyclohexanol and the solvent properties of acetone are used to synergistically regulate the reaction environment, promoting the formation of oxygen-rich W6466 under mild conditions. 18 O 49 The precursor avoids structural damage caused by high-temperature, strong reducing agents, laying the foundation for the subsequent construction of a highly active catalytic interface. After thorough stirring, a hydrothermal reaction is carried out to produce W... 18 O 49 Self-assembly into one-dimensional nanowire bundles, their three-dimensional stacking structure increases the specific surface area to expose more active sites and forms continuous electron transport channels to improve the insulation properties of the sulfur cathode. Washing and drying remove residual solvents and impurities, ensuring W 18 O 49 The cleanliness of the powder surface provides an ideal substrate for the uniform loading of palladium. W 18 O 49 The powder dissolves in a palladium acetate solution, leveraging the stable solubility of palladium acetate in polar aprotic solvents to precisely anchor palladium ions to W. 18 O 49 Oxygen vacancy sites. During the water bath reaction, the mild thermal conditions combined with continuous stirring promote the slow reduction of palladium ions into nanoparticles, avoiding aggregation and achieving the desired reaction between Pd nanoparticles and W.18 O 49 The matrix exhibits tight heterogeneous interface bonding. A repeated washing and drying process maintained the integrity of the nanostructure, ultimately yielding a three-dimensional stacked nanobundle structure in which electrons flow from W... 18 O 49 The directional transfer of oxygen defect sites to Pd nanoparticles significantly improves the adsorption and conversion efficiency of polysulfides.

[0017] Furthermore, a stable hydrothermal precursor system was constructed by precisely controlling the ratio of cyclohexanol, acetone, and hexachloride. In this system, the amount of cyclohexanol ensured that the reduction reaction proceeded within a suitable range, avoiding structural defects caused by excess; the amount of acetone maintained a homogeneous solvent mixture, providing a stable environment for the self-assembly of nanobundles; and the amount of hexachloride was precisely matched to the solvent system, ensuring a sufficient supply of tungsten atoms while effectively suppressing the formation of impurity phases. This proportional relationship worked together to improve the construction process of the hydrothermal precursor, directly enhancing W... 18 O 49 The controllability of powder purity and morphology lays the structural foundation for the subsequent uniform loading of palladium nanoparticles and electron transfer at heterogeneous interfaces.

[0018] Furthermore, homogenization of the reactant system is first achieved through a room-temperature stirring step. This operation, while avoiding interference from temperature fluctuations, ensures the complete dissociation and uniform distribution of hexachloride in the cyclohexanol-acetone mixed solvent, thereby eliminating the risk of component segregation. Subsequently, under precisely set hydrothermal reaction conditions, the precursor solution undergoes nucleation, growth, and self-assembly processes within the thermodynamic stability window. The temperature range of 150–180°C satisfies both W… 18 O 49 The energy requirements for the directional stretching of nanowires are minimized, while lattice distortion caused by high temperatures is prevented. The reaction time of 8 to 12 hours ensures that the nanowires are fully bundled and form a three-dimensional ordered stacked structure, thereby enhancing the specific surface area and electron transport capability of the material.

[0019] Furthermore, the synergistic effect of ethanol and water achieves stepwise removal of impurities: ethanol preferentially dissolves organic impurities to form a mobile phase, while water subsequently replaces residual ions. The negative pressure environment generated during filtration accelerates solvent penetration through the powder gaps, and the dynamic rinsing mechanism significantly improves impurity removal efficiency. During the vacuum drying stage, oxygen defect stability is maintained at a low temperature of 60–80 °C, and the vacuum environment effectively blocks oxygen diffusion paths. A precise balance between dehydration efficiency and structural stress control is achieved within a 15–30 min time period, thus ensuring W 18 O 49 The cleanliness of the powder surface and the integrity of the nanobundle structure lay the foundation for the uniform nucleation of Pd nanoparticles and the construction of heterogeneous interfaces.

[0020] Furthermore, stable Pd is formed using N,N dimethylformamide as a solvent. 2+ -DMF coordination intermediates, combined with palladium acetate solutions in the concentration range of 0.5~0.8 mmol / L, enabled the Pd... 2+ The slow release and uniform reduction of ions make Pd 2+ Ions in W 18 O 49 The surface is uniformly reduced to Pd 0 This forms uniformly sized Pd nanoparticles, thereby strengthening the bond between Pd nanoparticles and W. 18 O 49 Heterointerface contact between substrates allows electrons to escape from W. 18 O 49 The efficient transfer of oxygen defect sites to Pd nanoparticles provides a stable channel. In three-dimensionally stacked Pd-W nanobundles... 18 O 49 Precise control of the loading amount of Pd nanoparticles during material preparation presents a challenge. If Pd and W... 18 O 49 An improper mass ratio may lead to uneven distribution or excessive aggregation of Pd nanoparticles, disrupting the stability of the heterostructure and weakening the electron transfer from W. 18 O 49 The efficiency of oxygen defect site transfer to Pd affects the catalytic activity of sodium polysulfide conversion reaction, and thus cannot effectively suppress the "shuttle effect" in sodium-sulfur batteries.

[0021] Furthermore, by combining Pd with W 18 O 49 The mass ratio is strictly limited to the range of 0.01 to 0.05 to ensure that Pd nanoparticles are uniformly dispersed in W during the mixing process. 18 O 49 Nanobundle surface. When the mass ratio is not less than 0.01, sufficient Pd nanoparticles are provided to form effective catalytic active sites; when the mass ratio is not greater than 0.05, excessive aggregation of Pd nanoparticles is prevented. This ratio control promotes the interaction between Pd nanoparticles and W. 18 O 49 The close contact between oxygen vacancy sites optimizes electron transfer from W 18 O 49 The directional transfer pathway to Pd enhances the catalytic efficiency of the material for the conversion of sodium polysulfides. Effective control of the Pd nanoparticle loading ensures the stability of the heterostructure interface, enhances electron transfer efficiency, and thus improves the catalytic activity of the sodium polysulfide conversion reaction, effectively suppressing the shuttle effect in sodium-sulfur batteries.

[0022] Furthermore, a stirring rate of 300-500 r / min is used to maintain a uniform mixing state of the solution system, preventing localized excessive concentrations due to insufficient stirring or turbulence interference caused by excessive stirring, thus ensuring the uniform mixing of Pd. 2+ A stable coordination intermediate is formed in N,N dimethylformamide solvent and slowly reduced to Pd. 0 The conditions of 50-60℃ water bath for 6-10h precisely match the dissociation kinetics of coordination intermediates at this temperature, avoiding both excessively high temperatures that accelerate side reactions and excessively low temperatures that prolong the reaction cycle, ensuring that the reaction time is sufficient to complete interfacial electron transfer without damaging the morphology of the nanobundles; the conditions of 60-80℃ vacuum drying for 15-30min utilize the low-temperature vacuum environment to rapidly remove solvents, preventing lattice distortion or nanoparticle sintering caused by conventional high-temperature drying, adapting to the solvent evaporation characteristics of the material's pore structure, and effectively maintaining the specific surface area and oxygen defect activity of the three-dimensionally stacked nanobundles.

[0023] This invention discloses a three-dimensional stacked nanobundle Pd-W 18 O 49 The material, through the design of a three-dimensional stacked nanobundle structure, provides a larger specific surface area to significantly increase the number of catalytic active sites, and the orderly stacking of nanobundles constructs a highly efficient electron transport channel, effectively improving the electron conduction barrier caused by the insulating properties of sulfur cathodes; simultaneously, Pd nanoparticles are uniformly loaded onto W 18 O 49 The heterogeneous interface formed on the matrix causes electrons to move from W... 18 O 49 The oxygen defect sites are directionally transferred to Pd nanoparticles, which synergistically reduces the energy barrier of sodium polysulfide conversion reaction, especially accelerating the liquid-solid and solid-solid phase transition processes. This reduces the dissolution and migration of polysulfides, effectively suppresses the shuttle effect, and improves the cycle stability and charge-discharge efficiency of the battery.

[0024] Furthermore, by combining Pd nanoparticles with W 18 O 49 By constructing heterojunctions with clearly defined electron transfer directions between the matrices, electrons can be transferred from W... 18 O 49 The oxygen defect sites flow directionally into the Pd nanoparticles. This interface structure ensures the W 18 O 49The oxygen defect sites form close contact with Pd nanoparticles, preventing interruption of electron transport pathways. Directed electron transfer enhances the electron density and reducing power of Pd nanoparticles, optimizes their adsorption and activation process for sodium polysulfides, effectively lowers the reaction energy barrier, promotes the reaction kinetics of liquid-solid and solid-solid conversion stages, and stabilizes the interfacial structure, inhibiting the dissolution and shuttle behavior of polysulfides. This application enables the effective transfer of electrons from oxygen defect sites to Pd nanoparticles, fully activating catalytically active sites, improving sodium polysulfide conversion kinetics, and optimizing the cycle stability of sodium-sulfur batteries.

[0025] The three-dimensional stacked nanobundles Pd-W disclosed in this invention 18 O 49 The application of this material in the preparation of room-temperature sodium-sulfur battery cathode catalysts involves combining a three-dimensional stacked nanobundle structure with Pd-W 18 O 49 The heterogeneous interface combines in a synergistic catalytic manner, effectively accelerating the reaction kinetics of sodium polysulfide in the liquid-solid and solid-solid conversion stages and inhibiting the dissolution and migration of polysulfides, thereby improving battery cycle stability and energy conversion efficiency. Specifically, the design of the three-dimensional stacked nanobundle structure significantly increases the specific surface area and the number of catalytic active sites. Simultaneously, the ordered stacking of the nanobundles constructs continuous electron transport channels, effectively improving the electron conduction problem of the sulfur cathode; Pd nanoparticles and W... 18 O 49 The heterogeneous interface formed by the matrix utilizes W 18 O 49 The abundant oxygen defect sites in the sodium-sulfur battery act as electron donors, promoting the directional transfer of electrons to Pd nanoparticles, enhancing the synergistic catalytic effect, accelerating the conversion reaction of sodium polysulfides, lowering the reaction energy barrier, and suppressing the "shuttle effect." Through this technical solution, the charge-discharge efficiency, cycle stability, and actual capacity of room-temperature sodium-sulfur batteries are significantly improved, providing reliable technical support for large-scale energy storage applications. Attached Figure Description

[0026] Figure 1 Pd-W prepared in Example 3 18 O 49 XRD patterns of powder materials; Figure 2 The three-dimensional stacked nanobundles Pd-W prepared in Example 3 18 O 49 XPS spectra of the materials; where (a) represents W 4f; (b) represents O 1s; and (c) represents Pd 3d. Figure 3 The three-dimensional stacked nanobundles Pd-W prepared in Example 3 18 O 49 SEM images of the material; Figure 4 The three-dimensional stacked nanobundles Pd-W prepared in Example 3 18 O 49 Material cycle performance diagram; Figure 5 The three-dimensional stacked nanobundles Pd-W prepared in Example 3 18 O 49 Ratio performance diagram of the material. Detailed Implementation

[0027] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Unless otherwise specified, all embodiments and preferred embodiments mentioned herein can be combined to form new technical solutions.

[0029] Unless otherwise specified, all the technical features and preferred features mentioned herein can be combined to form new technical solutions.

[0030] In this invention, unless otherwise specified, percentage (%) or parts refer to weight percentage or parts relative to the composition.

[0031] Unless otherwise specified, the components or preferred components involved in this invention can be combined with each other to form new technical solutions.

[0032] In this invention, unless otherwise specified, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "6~22" indicates that all real numbers between "6~22" have been listed in this document, and "6~22" is simply a shortened representation of these numerical combinations.

[0033] The "scope" disclosed in this invention can be in the form of a lower limit and an upper limit, and can be one or more lower limits and one or more upper limits, respectively.

[0034] In this invention, the term "and / or" as used herein refers to any combination of one or more of the associated listed items, as well as all possible combinations, and includes such combinations.

[0035] In this invention, unless otherwise stated, the various reactions or operation steps may be performed sequentially or in a particular order. Preferably, the reaction methods described herein are performed sequentially.

[0036] Unless otherwise stated, the technical and scientific terms used herein have the same meanings as those familiar to those skilled in the art. Furthermore, any methods or materials similar to or equivalent to those described herein may also be used in this invention.

[0037] The three-dimensional stacked nanobundles Pd-W disclosed in this invention 18 O 49 The method for preparing the material includes the following steps: 1) Measure 10-20 mL of cyclohexanol and 40-50 mL of acetone and add them to a beaker, then stir for 5 min; 2) Weigh 0.003~0.005 mol of hexachloride and add it to the above solution, then stir at room temperature for 5~15 min; 3) Transfer the mixed solution into a 100 mL reaction vessel, seal it, and place it in an oven. React at 150-180°C for 8-12 h. 4) After the reaction is complete, wash the product with ethanol and water by vacuum filtration, then dry it in a vacuum oven at 60-80 °C for 15-30 min, and collect W. 18 O 49 Powder.

[0038] 5) Dissolve palladium acetate in N,N dimethylformamide to prepare a solution of 0.5-0.8 mmol / L.

[0039] 6) Press Pd and W 18 O 49 The mass ratio is 0.01~0.05, and the W obtained in step 4) 18 O 49 Dissolve the powder in the solution prepared in step 5), bathe in a water bath at 50-60℃ for 6-10 hours, and stir at 300-500 r / min.

[0040] 7) After the reaction is complete, the product is washed three times each with N,N dimethylformamide and ethanol by vacuum filtration, and then dried in a vacuum oven at 60-80 °C for 15-30 min to obtain the three-dimensional stacked nanobundles Pd-W. 18 O 49 Material.

[0041] The core equipment used in this invention includes a beaker (for stirring), a 100mL reaction vessel (for solvothermal processing), an oven (for drying), and a water bath (for Pd loading). These are all common equipment used in laboratories and industrial production, eliminating the need for costly custom-made special devices (such as plasma deposition equipment or high-pressure reaction vessels). Furthermore, each batch can prepare 1-5g of Pd-W. 18 O 49 Powders can be mass-produced at the kilogram level by increasing the volume of the reactor (e.g., 1L, 10L), making them highly adaptable to industrialization.

[0042] The raw materials used in this invention (cyclohexanol, acetone, tungsten hexachloride, palladium acetate, DMF, and ethanol) are all conventional reagents in the chemical industry, requiring no custom synthesis and resulting in low procurement costs; and no highly toxic reagents (such as thiols and heavy metal salts) or flammable and explosive solvents (such as diethyl ether and methanol) are used throughout the process.

[0043] The straight array W prepared in this invention 18 O4 material exhibits excellent catalytic performance as a cathode material in sodium-sulfur batteries. Within a voltage range of 0.2–3.0 V, 0.2 A g… -1 At current density, it exhibits approximately 900 mAh g after 300 cycles. -1 It has a high specific capacitance. It also exhibits excellent rate performance, with minimal capacitance difference at different current densities, maintaining stable capacitance, and retaining capacitance even at low current densities.

[0044] N,N-Dimethylformamide (DMF), as a polar aprotic solvent, can stabilize the solution state of palladium acetate (forming Pd). 2+ -DMF coordination intermediate), a combination of 60°C water bath and 300r / min stirring can slowly release Pd 2+ To make it in W 18 O 49 Surface uniform reduction deposition (Pd) 2+ →Pd 0 ), forming Pd nanoparticles, and with W 18 O 49 The matrix forms a tight heterogeneous interface—an interface that facilitates electron movement from W. 18 O 49 The oxygen defect sites are transferred to Pd, which significantly improves catalytic efficiency.

[0045] The three-dimensional stacked nanobundle structure Pd-W prepared by this invention 18 O 49 The material is used as a catalyst for the sulfur cathode in room-temperature sodium-sulfur batteries. This unique three-dimensional stacked nanobundle structure provides a larger specific surface area, increasing the number of catalytically active sites; furthermore, the ordered stacking of the nanobundles helps to construct fast electron transport channels, improving the electron conduction problem of the sulfur cathode. This material benefits from its abundant oxygen vacancies and Pd and W... 18 O 49 The synergistic catalytic effect effectively accelerates the conversion reaction of sodium polysulfide, reduces the reaction energy barrier, suppresses the "shuttle effect", and improves the charge and discharge efficiency, cycle stability and actual capacity of the battery, bringing a new breakthrough to the performance improvement of sodium-sulfur batteries and promoting their practical application in the field of large-scale energy storage.

[0046] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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 some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0047] Example 1 A three-dimensional stacked nanobundle Pd-W 18 O 49 Methods for preparing materials include: 1) Measure 10 mL of cyclohexanol and 50 mL of acetone and add them to a beaker, then stir for 5 min; 2) Weigh 0.003 mol of hexachloride and add it to the above solution, then stir at room temperature for 5 min; 3) Transfer the mixed solution into a 100 mL reaction vessel, seal it, and place it in an oven at 150 °C for 12 h; 4) After the reaction is complete, the product is washed with ethanol and water by vacuum filtration, then dried in a vacuum oven at 60 °C for 30 min, and W is collected. 18 O 49 Powder.

[0048] 5) Dissolve palladium acetate in N,N dimethylformamide to prepare a 0.5 mmol / L solution.

[0049] 6) Press Pd and W 18 O 49 The mass ratio of W obtained from 4) is 0.01. 18 O 49 The powder is dissolved in the solution prepared in step 5), and the mixture is placed in a water bath at 50°C for 10 hours while being stirred at 300 r / min.

[0050] 7) After the reaction is complete, the product is washed three times each with N,N dimethylformamide and ethanol by vacuum filtration, then dried in a vacuum oven at 60 °C for 30 min to obtain Pd-W. 18 O 49 Powder.

[0051] Example 2 A three-dimensional stacked nanobundle Pd-W 18 O 49 Methods for preparing materials include: 1) Measure 15 mL of cyclohexanol and 45 mL of acetone and add them to a beaker, then stir for 5 min; 2) Weigh 0.004 mol of hexachloride and add it to the above solution, then stir at room temperature for 10 min; 3) Transfer the mixed solution into a 100 mL reaction vessel, seal it, and place it in an oven at 160 °C for 10 h; 4) After the reaction is complete, the product is washed with ethanol and water by vacuum filtration, then dried in a vacuum oven at 70 °C for 20 min, and W is collected. 18 O 49 Powder.

[0052] 5) Dissolve palladium acetate in N,N dimethylformamide to prepare a 0.6 mM / L solution.

[0053] 6) Press Pd and W 18 O 49 The mass ratio of W obtained from step 4) is 0.02. 18 O 49 The powder was dissolved in the solution prepared in step 5), and the mixture was placed in a water bath at 55°C for 8 hours with stirring at 400 r / min.

[0054] 7) After the reaction is complete, the product is washed three times each with N,N dimethylformamide and ethanol by vacuum filtration, then dried in a vacuum oven at 70 °C for 20 min to obtain Pd-W. 18 O 49 Powder.

[0055] Example 3 A three-dimensional stacked nanobundle Pd-W 18 O 49 Methods for preparing materials include: 1) Measure 20 mL of cyclohexanol and 45 mL of acetone and add them to a beaker, then stir for 5 min; 2) Weigh 0.004 mol of hexachloride and add it to the above solution, then stir at room temperature for 10 min; 3) Transfer the mixed solution into a 100 mL reaction vessel, seal it, and place it in an oven at 170 °C for 10 h; 4) After the reaction is complete, the product is washed with ethanol and water by vacuum filtration, then dried in a vacuum oven at 75 °C for 15 min, and W is collected. 18 O 49 Powder.

[0056] 5) Dissolve palladium acetate in N,N dimethylformamide to prepare a 0.7 mM / L solution.

[0057] 6) Press Pd and W 18 O49 The mass ratio of W obtained from step 4) is 0.04. 18 O 49 The powder was dissolved in the solution prepared in step 5), and the mixture was placed in a water bath at 55°C for 7 hours while being stirred at 400 r / min.

[0058] 7) After the reaction is complete, the product is washed three times each with N,N dimethylformamide and ethanol by vacuum filtration, then dried in a vacuum oven at 70 °C for 20 min to obtain Pd-W. 18 O 49 Powder.

[0059] Figure 1 The Pd-W prepared in Example 3 of this invention 18 O 49 XRD patterns of powder materials; analysis of the product obtained in Example 3, XRD patterns of the product are shown in the appendix. Figure 1 The peak positions were consistent with the standard card, and no impurity peaks appeared, indicating that Pd-W was successfully prepared. 18 O 49 .

[0060] Figure 2 The three-dimensional stacked nanobundles Pd-W prepared in Example 3 18 O 49 XPS spectra of the materials; where (a) represents W 4f; (b) represents O 1s; and (c) represents Pd 3d; from Figure 2 As can be seen from the XPS image, Pd successfully handled the load at W. 18 O 49 surface.

[0061] Figure 3 The three-dimensional stacked nanobundles Pd-W prepared in Example 3 18 O 49 SEM images of the material; the sample was observed under a scanning electron microscope, from... Figure 3 As can be seen, the product exhibits one-dimensional nanowires self-assembling into bundles, and then the nanobundles are crisscrossed and stacked in three dimensions.

[0062] Figure 4 The three-dimensional stacked nanobundles Pd-W prepared in Example 3 18 O 49 Material cycle performance diagram; Figure 5 The three-dimensional stacked nanobundles Pd-W prepared in Example 3 18 O 49The rate performance diagram of the material; the obtained product was prepared into a button-type sodium-sulfur battery. The specific encapsulation steps are as follows: the active powder, conductive agent (Super P), carbon nanotubes, and binder (polyvinylidene fluoride PVDF) were ground evenly in a mass ratio of 7:1:1:1 to form a slurry. The slurry was then evenly coated onto copper foil using a coating machine and dried in a vacuum drying oven at 80℃ for 24 hours. Afterwards, the electrode sheets were assembled into a sodium-sulfur battery, and the battery was subjected to constant current charge-discharge testing using a Blue Electric electrochemical workstation. The test voltage was 0.2-3.0V. Figure 4 As shown, the battery at 0.2 A g -1 It exhibited approximately 900 mAh g at a current density. -1 Its capacity. Its rate performance is as follows: Figure 5 As shown, the capacity difference is small under different current densities, and the capacity remains stable. When returning to a low current density, the capacity can be maintained, indicating that its rate performance and cycle stability are good.

[0063] Example 4 A three-dimensional stacked nanobundle Pd-W 18 O 49 Methods for preparing materials include: 1) Measure 20 mL of cyclohexanol and 45 mL of acetone and add them to a beaker, then stir for 5 min; 2) Weigh 0.0045 mol of hexachloride and add it to the above solution, then stir at room temperature for 15 min; 3) Transfer the mixed solution into a 100 mL reaction vessel, seal it, and place it in an oven at 175°C for 9 h; 4) After the reaction is complete, the product is washed with ethanol and water by vacuum filtration, then dried in a vacuum oven at 70 °C for 15 min, and W is collected. 18 O 49 Powder.

[0064] 5) Dissolve palladium acetate in N,N dimethylformamide to prepare a 0.8 mmol / L solution.

[0065] 6) Press Pd and W 18 O 49 The mass ratio of W obtained from step 4) is 0.045. 18 O 49 The powder is dissolved in the solution prepared in step 5), and the mixture is placed in a water bath at 60°C for 6 hours while being stirred at 500 r / min.

[0066] 7) After the reaction is complete, the product is washed three times each with N,N dimethylformamide and ethanol by vacuum filtration, then dried in a vacuum oven at 75 °C for 15 min to obtain Pd-W. 18 O 49 Powder.

[0067] Example 5 A three-dimensional stacked nanobundle Pd-W 18 O 49 Methods for preparing materials include: 1) Measure 20 mL of cyclohexanol and 40 mL of acetone and add them to a beaker, then stir for 5 min; 2) Weigh 0.005 mol of hexachloride and add it to the above solution, then stir at room temperature for 15 min; 3) Transfer the mixed solution into a 100 mL reaction vessel, seal it, and place it in an oven at 180°C for 8 h; 4) After the reaction is complete, the product is washed with ethanol and water by vacuum filtration, then dried in a vacuum oven at 80 °C for 15 min, and W is collected. 18 O 49 Powder.

[0068] 5) Dissolve palladium acetate in N,N dimethylformamide to prepare a 0.8 mmol / L solution.

[0069] 6) Press Pd and W 18 O 49 The mass ratio of W obtained from step 4) is 0.05. 18 O 49 The powder was dissolved in the solution prepared in step 5), and the mixture was placed in a water bath at 60°C for 9 hours while being stirred at 300 r / min.

[0070] 7) After the reaction is complete, the product is washed three times each with N,N dimethylformamide and ethanol by vacuum filtration, then dried in a vacuum oven at 70 °C for 15 min to obtain Pd-W. 18 O 49 Powder.

[0071] In summary, this invention provides a three-dimensional stacked nanobundle Pd-W 18 O 49 Materials, preparation methods, and applications: A three-dimensional stacked nanobundle structure of Pd-W was designed and prepared. 18 O 49 A composite material with a unique microstructure exhibiting high specific surface area and fast electron transport channels was constructed using a solvothermal method combined with a water bath loading process. This material utilizes W... 18 O 49 The abundant oxygen vacancies and the synergistic catalytic effect of Pd nanoparticles significantly accelerate the conversion kinetics of sodium polysulfides, suppress the "shuttle effect," and thus improve the battery's conductivity and reaction efficiency. At 0.2 A g... -1 It still maintains approximately 900 mAh g after 300 cycles at current density. -1It boasts high specific capacity, excellent rate performance, and strong capacity recovery capability; at the same time, the preparation process is simple, the raw material cost is low, the equipment is highly versatile, and it is easy to scale up production, providing an efficient and reliable catalyst solution for large-scale energy storage applications of room temperature sodium-sulfur batteries.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A three-dimensional stacked nanobundle Pd-W 18 O 49 The method for preparing the material is characterized by, include: Cyclohexanol and acetone were mixed thoroughly, then hexachloride was added and stirred until homogeneous. After hydrothermal reaction, washing, and drying, W was obtained. 18 O 49 Powder; W 18 O 49 The powder was dissolved in palladium acetate solution, reacted in a water bath, washed again, and dried again to obtain three-dimensional stacked nanobundles of Pd-W. 18 O 49 Material.

2. The three-dimensional stacked nanobundles Pd-W according to claim 1 18 O 49 The method for preparing the material is characterized by, The ratio of the amount of cyclohexanol, acetone and hexachloride used is (10~20) mL: (40~50) mL: (0.003~0.005) mol.

3. The three-dimensional stacked nanobundles Pd-W according to claim 1 18 O 49 The method for preparing the material is characterized by, The stirring conditions are: stirring at room temperature for 5-15 minutes; the hydrothermal reaction conditions are: reaction at 150-180℃ for 8-12 hours.

4. The three-dimensional stacked nanobundles Pd-W according to claim 1 18 O 49 The method for preparing the material is characterized by, The washing conditions are: washing with ethanol and water by vacuum filtration; the drying conditions are: vacuum drying at 60~80 ℃ for 15~30 min.

5. The three-dimensional stacked nanobundles Pd-W according to claim 1 18 O 49 The method for preparing the material is characterized by, The palladium acetate solution is prepared by dissolving palladium acetate in N,N dimethylformamide; the molar concentration of the palladium acetate solution is 0.5~0.8 mmol / L.

6. The three-dimensional stacked nanobundles Pd-W according to claim 1 18 O 49 The method for preparing the material is characterized by, The W 18 O 49 When the powder is mixed with the palladium acetate solution, the ratio of Pd to W is as follows: 18 O 49 The mass ratio is (0.01~0.05):1 for mixing.

7. The three-dimensional stacked nanobundles Pd-W according to claim 1 18 O 49 The method for preparing the material is characterized by, The conditions for the water bath reaction are: stirring at a rate of 300-500 r / min, in a water bath at 50-60℃ for 6-10 h; The drying conditions are: vacuum drying at 60~80℃ for 15~30 min.

8. A three-dimensional stacked nanobundle Pd-W 18 O 49 The material is characterized by, The three-dimensional stacked nanobundles Pd-W as described in any one of claims 1 to 7 18 O 49 The material was prepared using a specific method.

9. The three-dimensional stacked nanobundles Pd-W according to claim 8 18 O 49 The material is characterized by, The three-dimensional stacked nanobundles Pd-W 18 O 49 In the material, Pd nanoparticles and W 18 O 49 At the heterogeneous interface formed by the matrix, electrons from W 18 O 49 Oxygen defect sites in the matrix are transferred to Pd nanoparticles.

10. The three-dimensional stacked nanobundles Pd-W according to any one of claims 1 to 7 18 O 49 Three-dimensional stacked nanobundles Pd-W prepared by material preparation method 18 O 49 Application of the material in the preparation of catalysts for room temperature sodium-sulfur battery cathode materials.

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