Tungsten disulfide / tungsten diselenide electrode material, preparation method and application thereof

Abstract

This invention belongs to the technical field of potassium-ion battery electrode materials. It discloses tungsten disulfide / tungsten diselenide electrode materials, their preparation methods, and their applications. The method involves mechanically mixing bulk tungsten disulfide / tungsten diselenide materials obtained through high-temperature reactions with small-sized ionic liquids or small organic molecules. The ionic liquids or small molecules act as intercalating agents, inserting into the interlayer spaces of the tungsten disulfide / tungsten diselenide molecules to regulate the interlayer structure, resulting in expanded and exfoliated ultra-dispersed tungsten disulfide / tungsten diselenide materials. Ferromagnetic metal cations are then introduced into these ultra-dispersed tungsten disulfide / tungsten diselenide materials to obtain ferromagnetically doped ultra-dispersed tungsten disulfide / tungsten diselenide electrode materials. This invention utilizes a combined "intercalation-exfoliation-cation doping" strategy to obtain tungsten disulfide / tungsten diselenide electrode materials with large interlayer spacing, small size, few layers, ultra-dispersion, and certain ferromagnetic properties, suitable for use as a negative electrode material in potassium-ion batteries, achieving a capacity of up to 336 mAh·g. ‑1 .

Description

Technical Field

[0001] This invention belongs to the field of potassium-ion battery electrode material technology, and particularly relates to tungsten disulfide / tungsten diselenide electrode materials, preparation methods and applications. Background Technology

[0002] With the widespread application of lithium-ion batteries, the high cost caused by insufficient lithium resources has severely limited their promotion and application in large-scale energy storage deployments. Developing alternative rechargeable battery technologies based on low cost and abundant resources to compensate for the shortcomings of lithium-ion batteries has become extremely urgent and important. Potassium-ion batteries, belonging to the same Group I elements and possessing similar properties, are highly anticipated among all alkali metal-ion battery systems due to their higher natural abundance than lithium, lower redox potential than sodium, wide availability, and low price. While research on potassium-ion batteries has grown rapidly in recent years, it remains in its initial stages, with many problems still needing to be solved.

[0003] Anode materials are a key component of potassium-ion batteries. Currently, the rate capacity and cycle stability of most potassium storage anode materials still cannot meet the requirements of high-rate, long-life potassium-ion batteries. Among these challenges, the biggest lies in the potassium ion radius. Much larger than the radius of a lithium ion and sodium ion radius This significantly reduces the rate at which potassium ions are inserted / extracted from the negative electrode material, thus limiting the capacity and rate performance of the electrode material. Simultaneously, the large ionic radius causes severe volume expansion in the electrode material, resulting in high mechanical stress / strain and severely reducing the battery's cycle life. This has become a key common problem restricting the development of potassium-ion batteries. Therefore, finding electrode materials with a radius matching that of potassium ions is crucial for fully realizing the performance of potassium-ion batteries.

[0004] Structurally, large ions require a large space to accommodate them. Compared to graphite (0.335 nm), two-dimensional layered transition metal chalcogenides (TMDs) with larger interlayer spacing (typically >0.6 nm) hold more potential for potassium ion storage because the larger interlayer spacing facilitates increased potassium ion diffusion rates. Tungsten-based chalcogenides (WX2, X = S, Se), as a novel type of TMD, have interlayer spacings close to those of materials such as MoS2 and MoSe2, and exhibit better performance than other TMDs (typically <300 cm). 2 V -1 s -1 Higher ion mobility (e.g., WS2 is close to 800 cm⁻¹) 2 V -1 s -1WX2 materials offer better rate performance for advanced rechargeable batteries. However, in practical studies, WX2 materials often exhibit poor rate performance and cycle stability. This is because WX2 materials are prone to aggregation during synthesis, which hinders the rapid diffusion and insertion of potassium ions. Secondly, WX2 materials undergo significant volume changes during charge and discharge, easily leading to pulverization and collapse of the electrode structure, resulting in poor cycle stability. To address this issue, common modification strategies include carbon-based composites, structural nanostructuring, and morphology control. However, these strategies often involve complex fabrication processes and drawbacks such as reduced battery volumetric energy density and increased side reactions.

[0005] Given the extremely weak interlayer van der Waals forces in WX2 materials, its interlayer structure possesses ample tunability and controllability, and changes in the interlayer structure can lead to improvements in various performance aspects. Therefore, WX2-based potassium storage materials can be optimized through methods such as layer expansion, exfoliation, and layer stacking. On the other hand, the space charge storage mechanism proposes that the formation and storage of a large number of spin-polarized electrons at ultra-high-density interfaces under low potentials generates a large amount of additional capacity, namely spin-polarized capacitance, thus causing the actual capacity exhibited by the electrode to anomalously exceed the theoretical capacity limit. This mechanism is very evident in lithium batteries, where the electron spin polarization effect contributes approximately 32% of the battery's additional energy density. Due to the limited types of electrode materials currently studied, the contribution rate can be inferred to be even higher. Guided by high energy / power density and long cycle life, in WX2-based anode materials for potassium-ion batteries, constructing a space charge storage mechanism by controlling the electron spin property serves as a new regulatory approach to effectively improve the electrochemical performance of WX2-based anode materials.

[0006] Based on the above analysis, the problems and shortcomings of the existing technology are as follows:

[0007] (1) Currently, with the widespread use of lithium-ion batteries, the high cost caused by insufficient lithium resources greatly limits their promotion and application in large-scale energy storage deployment.

[0008] (2) At present, the rate capacity and cycle stability of most potassium storage anode materials cannot meet the requirements of high-rate and long-life potassium-ion batteries, which limits the capacity and rate performance of electrode materials.

[0009] (3) Currently, WX2 materials with potassium storage potential often exhibit poor rate performance and cycle stability in practical applications. Summary of the Invention

[0010] To overcome the problems existing in related technologies, the present invention discloses tungsten disulfide / tungsten diselenide electrode materials, preparation methods, and applications, particularly relating to a ferromagnetic tungsten disulfide / tungsten diselenide electrode material, its preparation method, and its application in potassium-ion batteries. The technical solution is as follows:

[0011] This invention is achieved as follows: the method for preparing tungsten disulfide / tungsten diselenide electrode materials includes:

[0012] Step 1: Construct tungsten disulfide / tungsten diselenide; uniformly mix tungsten source, sulfur source or selenium source according to a certain stoichiometric molar ratio, and sinter in a vacuum quartz tube to obtain tungsten disulfide / tungsten diselenide bulk material;

[0013] Step 2, intercalation and exfoliation: The obtained sintered bulk material is dispersed in a small-sized pure ionic liquid or organic small molecule solvent and mixed. Under mechanical stirring, ultrasonic vibration and pressure conditions, the ionic liquid or small molecule is used as an intercalating agent to insert into the molecular layers of tungsten disulfide / tungsten diselenide bulk material to regulate the interlayer structure.

[0014] Step 3, ion doping; the expanded and exfoliated ultradispersed tungsten disulfide / tungsten diselenide bulk material is immersed in a boiling ferromagnetic metal salt solution. After soaking and stirring, the target product, ultradispersed tungsten disulfide / tungsten diselenide electrode material, doped with ferromagnetic metal cations, is obtained.

[0015] In one embodiment, the ferromagnetic metal cation includes Mn 2+ Fe 2+ / Fe 3+ Co 2+ Ni 2+ .

[0016] In step one, the tungsten source, sulfur source, or selenium source is first mechanically ground and then encapsulated in a vacuum quartz glass tube, and heated to react under an inert atmosphere.

[0017] In step one, a certain stoichiometric molar ratio is: tungsten source: sulfur source or selenium source = 1:2.

[0018] In step two, the small molecule solvent is any one or more of ethanol, ethylene glycol, glycerol, toluene, or acetone.

[0019] In step two, the pure ionic liquid is any one or more of [BMIm][BF4], [BMIm]Cl, [BMIm][PF6], [BMIm]Br, [BMIm][NO3], [BMIm][TA], [EMIm][BF4], [EMIm]Br, or [EMIm]I.

[0020] In step two, the interlayer structure includes the interlayer spacing, the sheet size, and the number of layers.

[0021] In step three, the ferromagnetic metal salt solution is any one or more of FeCl3, FeCl2, CoCl2, NiCl2, Fe(NO3)3, Co(NO3)2, or Ni(NO3)2.

[0022] Another object of the present invention is to provide an electrode material prepared by the method described above for preparing tungsten disulfide / tungsten diselenide electrode material, wherein the electrode material has 2-5 layers, an interlayer spacing of 0.72-1.10 nm, and the amount of ferromagnetic metal cations is controlled between 1.2-8.0 wt%.

[0023] Another object of the present invention is to provide an application of such electrode materials in the preparation of potassium-ion battery anode materials.

[0024] Combining all the above technical solutions, the advantages and positive effects of this invention are as follows:

[0025] First, in view of the technical problems existing in the prior art and the difficulty of solving these problems, and closely combining the technical solution to be protected by this invention with the results and data during the research and development process, this paper analyzes in detail how the technical solution of this invention solves the technical problems, and the inventive technical effects brought about after solving the problems, as described in detail below:

[0026] The ferromagnetic tungsten disulfide / tungsten diselenide electrode material provided by this invention possesses characteristics such as large interlayer spacing, small size, few layers, ultradispersion, and a certain degree of ferromagnetism. The preparation method employed in this invention combines a "layer expansion-exfoliation-cation doping" strategy. First, the bulk tungsten disulfide / tungsten diselenide material obtained from a high-temperature reaction is mechanically mixed with a small-sized ionic liquid or small organic molecule. The ionic liquid or small molecule acts as an intercalating agent, inserting into the interlayer spaces of the tungsten disulfide / tungsten diselenide molecules to regulate its interlayer structure, obtaining an expanded and exfoliated ultradispersed tungsten disulfide / tungsten diselenide material. Then, a certain amount of ferromagnetic metal cations (such as Mn) are introduced into the ultradispersed tungsten disulfide / tungsten diselenide material. 2+ Fe 2+ / Fe 3+ Co 2+ Ni 2+ (etc.), to obtain a superdispersed tungsten disulfide / tungsten diselenide electrode material doped with ferromagnetic metal cations. The ferromagnetic tungsten disulfide / tungsten diselenide electrode material provided by this invention can be used as a negative electrode material for potassium-ion batteries, with a capacity reaching 336 mAh·g. -1 .

[0027] This invention constructs "few-layer J-WX2" materials through two strategies: controlling the interlayer structure of tungsten disulfide / tungsten diselenide using ionic liquids or small molecules via "layer expansion-exfoliation," and anchoring ferromagnetic cations (J) through defect engineering. Layer expansion-exfoliation in situ controls the interlayer spacing and number of tungsten disulfide / tungsten diselenide layers, leveraging their inherent high conductivity to enhance spin shift and accelerate spin polarization kinetics; ion exchange reactions anchor ferromagnetic cations (such as Mn). 2+ Fe 2+ / Fe 3+ Co 2+ Ni 2+ By improving the electron delocalization and interfacial spin polarization electron density of the electrode material, and through the synergistic "intercalation-conversion" electrochemical reaction mechanism of the tungsten disulfide / tungsten diselenide-based electrode, the electronic spin state of the electrode material is effectively controlled, and additional spin polarization capacitance is generated at the interface. Ultimately, this invention yields a tungsten disulfide / tungsten diselenide electrode material for potassium-ion batteries with high energy / power density and long cycle life.

[0028] Compared with the prior art, the beneficial effects of the present invention are also reflected in:

[0029] (1) In terms of material preparation, in order to address the problem of poor reaction kinetics caused by the large radius of potassium ions, a "layer expansion-exfoliation" strategy is used to construct tungsten disulfide / tungsten diselenide materials with small size, large interlayer spacing and few layers; a "ferromagnetic cation doping" strategy is used to induce lattice distortion and form an unsaturated coordination structure, which causes changes in electron delocalization and spin polarization electron density near the Fermi level; the high conductivity, few layers and expanded structure enhance spin transfer and accelerate spin polarization kinetics, and the electrochemical reaction ("intercalation-conversion") inside the energy storage device is used as a control means to achieve efficient control of interface spin polarization electrons.

[0030] (2) Regarding the potassium storage mechanism of the material, spin-polarized electrons are constructed and controlled in the electrode to introduce additional capacity. The "intercalation reaction" in the J-WX2 energy storage process promotes the reaction kinetics and solves the problem of slow kinetics of the negative electrode material. The "conversion reaction" is used to alleviate the volume expansion and solve the problem of severe cycle life decay. The potential of the target product tungsten disulfide / tungsten diselenide electrode material is fully utilized, and the electrochemical performance is further improved.

[0031] Secondly, considering the technical solution as a whole or from the perspective of the product, the technical effects and advantages of the technical solution to be protected by this invention are specifically described as follows:

[0032] This invention belongs to the research field of tungsten disulfide / tungsten diselenide-based electrode materials for potassium-ion battery anodes. It provides a tungsten disulfide / tungsten diselenide electrode material and its preparation method, and applies the material to potassium-ion battery anodes. This invention utilizes a combined strategy of "layer expansion-exfoliation-cation doping" to obtain tungsten disulfide / tungsten diselenide electrode materials with large interlayer spacing, small size, few layers, hyperdispersion, and certain ferromagnetic properties. The tungsten disulfide / tungsten diselenide electrode material provided by this invention, as a potassium-ion battery anode, not only solves key common problems such as poor electrode reaction kinetics, large volume changes, and easy pulverization of active components, but more importantly, it can accelerate spin polarization kinetics and improve interfacial spin polarization capacitance by enhancing spin transfer.

[0033] Third, as supplementary evidence of the inventive step of the claims of this invention, it is also reflected in the following important aspects:

[0034] (1) This invention regulates the interlayer spacing and number of layers of WX2 through a "layer expansion-stripping-cation doping" strategy, improves its electrochemical kinetics, and solves the key constraint problem (K) of WX2 anode materials in potassium storage. + (Factors such as difficulty in insertion / extraction, high mechanical stress, and easy pulverization of active materials) are addressed by introducing ferromagnetic metal cations into WX2 material to regulate spin-polarized electrons and introduce additional capacity, thereby obtaining a WX2 potassium storage anode material with high rate performance, long cycle life, and high specific capacity. The implementation of this patent will provide guidance for the design of high-performance potassium storage anode materials and also serve as a reference for the research of high-performance electrode materials for other energy storage devices.

[0035] (2) This invention constructs a tungsten disulfide / tungsten diselenide electrode material with large interlayer spacing, small size, few layers, super-dispersion, and certain ferromagnetic properties through a "layer expansion-stripping-cation doping" strategy. Based on the technical solution of basic structure regulation, by introducing ferromagnetic metal cations to improve the electronic delocalization and interfacial spin polarization electron density of the electrode material, an additional spin polarization capacity based on the "intercalation-conversion" electrochemical reaction mechanism is proposed.

[0036] (3) Potassium ion radius Much larger than the radius of a lithium ion and sodium ion radius This significantly reduces the rate of insertion / extraction of the ionic component into the anode material, thus limiting the capacity and rate performance of the electrode material. Simultaneously, the large ionic radius causes severe volume expansion in the electrode material, resulting in high mechanical stress / strain and severely reducing the battery's cycle life. This has become a key common problem restricting the development of potassium-ion batteries. The modification strategy based on WX2 material proposed in this invention not only enables the controllable preparation of anode materials with high rate performance, long cycle life, and high specific capacity, but also provides new ideas and solutions for the research of high-performance electrode materials for other energy storage devices.

[0037] (4) The modification strategy based on WX2 material proposed in this invention overcomes the defects of WX2 material in practical applications, enabling the potassium storage anode material with strong theoretical feasibility to show excellent potassium storage performance in practical applications. Attached Figure Description

[0038] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure;

[0039] Figure 1 This is a flowchart of the method for preparing tungsten disulfide / tungsten diselenide electrode material provided in the embodiments of the present invention;

[0040] Figure 2 This is a schematic diagram of the method for preparing tungsten disulfide / tungsten diselenide electrode materials provided in the embodiments of the present invention;

[0041] Figure 3 These are scanning electron microscope (SEM) images of the WS2 material provided in Embodiment 1 of the present invention;

[0042] Figure 4 These are scanning electron microscope (SEM) images of the ultradispersed WS2 material provided in Embodiment 2 of the present invention;

[0043] Figure 5 These are scanning electron microscope (SEM) images of the ferromagnetic cation-doped Fe-WS2 material provided in Example 3 of this invention;

[0044] Figure 6 These are the XRD patterns of the WS2 material provided in Examples 1-3 of this invention;

[0045] Figure 7 When the WS2 material provided in Examples 1-3 of this invention is used as the negative electrode of a potassium-ion battery, at 0.05 A·g -1 A schematic diagram of the second charge-discharge data under current density;

[0046] Figure 8 When the WS2 material provided in Examples 1-3 of this invention is used as the negative electrode of a potassium-ion battery, at 2A·g-1 A schematic diagram of cycling performance data at current density. Detailed Implementation

[0047] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0048] I. Explanation of the Implementation Example:

[0049] like Figure 1 As shown, the method for preparing tungsten disulfide / tungsten diselenide electrode material provided in this embodiment of the invention includes the following steps:

[0050] S101, tungsten disulfide / tungsten diselenide bulk material is obtained by uniformly mixing tungsten source and sulfur source (or selenium source) in a certain stoichiometric molar ratio and reacting and sintering at high temperature in a vacuum quartz tube.

[0051] S102 involves dispersing the sintered sample in a pure ionic liquid or small molecule solvent, and then, under mechanical stirring, ultrasonic vibration, or high pressure conditions, inserting ions or small molecules into the interlayer of the tungsten disulfide / tungsten diselenide material to regulate the interlayer structure.

[0052] S103, the expanded and exfoliated tungsten disulfide / tungsten diselenide material is immersed in a boiling ferromagnetic metal salt solution of a certain pH, and after soaking and stirring for a certain period of time, the target product tungsten disulfide / tungsten diselenide electrode material is obtained.

[0053] As a preferred embodiment, such as Figure 2 As shown, the method for preparing tungsten disulfide / tungsten diselenide electrode material provided in this embodiment of the invention specifically includes the following steps:

[0054] (a) Construction of tungsten disulfide / tungsten diselenide: A certain proportion of tungsten source and sulfur source (or selenium source) are mechanically ground at a stoichiometric molar ratio of 1:2, encapsulated in a vacuum quartz glass tube, transferred to a tube furnace, and reacted at high temperature under an inert atmosphere to obtain tungsten disulfide / tungsten diselenide bulk material.

[0055] (b) Intercalation and exfoliation: The sintered sample is mixed with pure ionic liquid or small molecule solvent. Small ions or molecules are used as layer expanders and are inserted into the molecular interlayer of tungsten disulfide / tungsten diselenide material under mechanical stirring, ultrasonic vibration or high pressure reaction to regulate its interlayer structure (interlayer spacing, lamellar size, number of layers);

[0056] (c) Ion doping: The stripped tungsten disulfide / tungsten diselenide material is immersed in a boiling ferromagnetic metal salt solution of a certain pH for metal cation exchange. The tungsten disulfide / tungsten diselenide parent material forms a large number of interfacial nucleation sites with the exogenous metal ions, inducing the defect sites to accurately anchor the ferromagnetic metal ions, thereby realizing the controllable in-situ construction of metal defects.

[0057] In step (b) of this embodiment of the invention, the small molecule solvent is one or more of the following types: ethanol, ethylene glycol, glycerol, toluene, acetone, etc.; the pure ionic liquid is one or more of the following types: [BMIm][BF4], [BMIm]Cl, [BMIm][PF6], [BMIm]Br, [BMIm][NO3], [BMIm][TA], [EMIm][BF4], [EMIm]Br, [EMIm]I, etc.

[0058] In step (c) of the present invention, the ferromagnetic metal salt solution is one or more of the following types: FeCl3, FeCl2, CoCl2, NiCl2, Fe(NO3)3, Co(NO3)2, Ni(NO3)2, etc.

[0059] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0060] The information interaction and execution process between the above-mentioned devices / units are based on the same concept as the method embodiments of the present invention. For details on their specific functions and technical effects, please refer to the method embodiments section, and they will not be repeated here.

[0061] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this invention. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments.

[0062] II. Application Examples:

[0063] The application embodiment of the present invention provides a target tungsten disulfide / tungsten diselenide electrode material prepared by implementing a method for preparing tungsten disulfide / tungsten diselenide electrode material. The number of layers of the target tungsten disulfide / tungsten diselenide electrode material can be reduced to 2-5 layers, the interlayer spacing can be expanded to 0.72-1.10 nm, and the amount of ferromagnetic metal cations can be controlled between 1.2-8.0 wt%.

[0064] The application embodiment of the present invention provides an application of ferromagnetic tungsten disulfide / tungsten diselenide electrode material in the preparation of potassium-ion battery anode materials.

[0065] This invention also provides a computer device comprising: at least one processor, a memory, and a computer program stored in the memory and executable on the at least one processor, wherein the processor executes the computer program to implement the steps in any of the above method embodiments.

[0066] This invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, can implement the steps described in the various method embodiments above.

[0067] This invention also provides an information data processing terminal, which, when executed on an electronic device, provides a user input interface to implement the steps described in the above method embodiments. The information data processing terminal is not limited to mobile phones, computers, or switches.

[0068] This invention also provides a server that, when executed on an electronic device, provides a user input interface to implement the steps described in the above method embodiments.

[0069] This invention provides a computer program product that, when run on an electronic device, enables the electronic device to implement the steps described in the various method embodiments above.

[0070] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments of this application can be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include at least: any entity or device capable of carrying the computer program code to a photographing device / terminal device, a recording medium, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium. Examples include USB flash drives, portable hard drives, magnetic disks, or optical disks.

[0071] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0072] III. Evidence of the relevant effects of the embodiments:

[0073] Example 1

[0074] This invention utilizes high-temperature preparation of WS2 material. Specifically, a certain proportion of S powder (128 mg) and WO3 powder (464 mg) are mechanically ground at a stoichiometric molar ratio of 2:1. After uniform grinding, the mixture is encapsulated in a vacuum quartz glass tube and sintered at 500°C for 2 hours in a tube furnace under argon atmosphere protection to obtain the WS2 material. Figure 3 As can be seen from the above, the WS2 material prepared in the embodiments of the present invention exhibits the morphology of nanoflowers.

[0075] Example 2

[0076] This invention relates to the preparation of ultradispersed WS2 material. The specific method is as follows: S powder (128 mg) and WO3 powder (464 mg) are mechanically ground at a stoichiometric molar ratio of 2:1. After uniform grinding, the mixture is encapsulated in a vacuum quartz glass tube and sintered at 500°C for 2 hours in a tube furnace under argon atmosphere to obtain initial WS2 bulk material. The sintered bulk material is then mixed with a certain amount of small-sized ionic liquid [BMIm]Cl (80 mg), followed by mechanical grinding and ultrasonic vibration to peel off the WS2 molecular layers. Finally, it is calcined again under argon atmosphere to remove excess ionic liquid, resulting in ultradispersed WS2 material with large interlayer spacing, small size, and few layers. Figure 4 As can be seen from the above, the WS2 material obtained in this embodiment of the invention is more dispersed than that in embodiment 1.

[0077] Example 3

[0078] This invention relates to the preparation of ferromagnetic cation-doped Fe-WS2 material. The specific method is as follows: S powder (128 mg) and WO3 powder (464 mg) are mechanically ground at a stoichiometric molar ratio of 2:1. After uniform grinding, the mixture is encapsulated in a vacuum quartz glass tube and sintered at 500°C for 2 hours in a tube furnace under argon atmosphere to obtain initial WS2 bulk material. The sintered bulk material is mixed with a certain amount of small-sized ionic liquid [BMIm]Cl (80 mg), then mechanically ground and ultrasonically vibrated to peel off the WS2 molecular layers. The mixture is then calcined again under argon atmosphere to remove excess ionic liquid, resulting in a super-dispersed WS2 material with large interlayer spacing, small size, and few layers. The super-dispersed WS2 material is dispersed in 100 mL of boiling Fe(NO3)3 solution (10 mM) for ion exchange for 60 s, then washed and dried to obtain the ferromagnetic cation-doped Fe-WS2 material. Figure 5 As can be seen from the above, the surface of the WS2 material obtained in this embodiment of the invention has many small protrusions, which may be caused by Fe ion doping. From... Figure 6 As can be seen from the above, the WS2 materials obtained in Examples 1 to 3 of the present invention all have good WS2 phase structures.

[0079] Example 4

[0080] The method provided in this embodiment of the invention is basically the same as that in embodiment 3, except that the ferromagnetic metal salt solution Fe(NO3)3 is replaced with Co(NO3)3 solution, while other conditions remain unchanged.

[0081] Example 5

[0082] The method provided in this embodiment of the invention is basically the same as that in embodiment 3, except that the ferromagnetic metal salt solution Fe(NO3)3 is replaced with Ni(NO3)2 solution, while other conditions remain unchanged.

[0083] Application Example 1

[0084] The WS2 material obtained in Examples 1-3 of this invention was mixed with a conductive agent (acetylene black) and a binder (polyvinylidene fluoride, PVDF) at a mass ratio of 70:15:15. This mixture was then added to 1-methyl-2-pyrrolidone (NMP) and thoroughly ground to form a slurry. The slurry was uniformly coated onto copper foil to form an electrode sheet. A potassium-ion battery was assembled in an argon-filled glove box. The electrochemical performance of the battery was tested using a blue electric test system. The test results are as follows: Figure 7 and Figure 8 As shown.

[0085] from Figure 7 It can be seen that the discharge capacity of the WS2 material obtained in Example 1 of this invention is 236 mAh·g. -1 The discharge capacity of the WS2 material obtained in Example 2 was 284 mAh·g. -1 The discharge capacity of the WS2 material obtained in Example 3 was 336 mAh·g. -1 The above results demonstrate that both the intercalation stripping strategy and the cation doping strategy improved the capacity of the WS2 material. Meanwhile, from... Figure 8 As can also be seen, the sample obtained in Example 3 of the present invention has the best cycling performance.

[0086] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention and within the spirit and principles of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing tungsten disulfide / tungsten diselenide electrode material, characterized in that, The method includes: Step 1: Construct tungsten disulfide / tungsten diselenide; uniformly mix tungsten source, sulfur source or selenium source according to a certain stoichiometric molar ratio, and sinter in a vacuum quartz tube to obtain tungsten disulfide / tungsten diselenide bulk material; Step 2, intercalation and exfoliation; the obtained sintered bulk material is dispersed in a small-sized pure ionic liquid or organic small molecule solvent and mixed. Under mechanical stirring, ultrasonic vibration and pressure conditions, the ionic liquid or small molecule acts as an intercalating agent to insert into the molecular layers of the tungsten disulfide / tungsten diselenide bulk material to regulate the interlayer structure; wherein, the small molecule solvent is any one or more of ethanol, ethylene glycol, glycerol, toluene or acetone, and the pure ionic liquid is any one or more of [BMIm][BF4], [BMIm]Cl, [BMIm][PF6], [BMIm]Br, [BMIm][NO3], [BMIm][TA], [EMIm][BF4], [EMIm]Br or [EMIm]I; Step 3, ion doping; the expanded and exfoliated ultradispersed tungsten disulfide / tungsten diselenide bulk material is immersed in a boiling ferromagnetic metal salt solution. After soaking and stirring, the target product, ultradispersed tungsten disulfide / tungsten diselenide electrode material, doped with ferromagnetic metal cations, is obtained; wherein the electrode material has 2-5 layers, an interlayer spacing of 0.72-1.10 nm, and the amount of ferromagnetic metal cations is controlled between 1.2-8.0 wt%.

2. The method for preparing tungsten disulfide / tungsten diselenide electrode material according to claim 1, characterized in that, Ferromagnetic metal cations include Mn 2+ Fe 2+ / Fe 3+ Co 2+ Ni 2+ .

3. The method for preparing tungsten disulfide / tungsten diselenide electrode material according to claim 1, characterized in that, In step one, the tungsten source, sulfur source, or selenium source is first mechanically ground and then encapsulated in a vacuum quartz glass tube, and heated to react under an inert atmosphere.

4. The method for preparing tungsten disulfide / tungsten diselenide electrode material according to claim 1, characterized in that, In step one, a certain stoichiometric molar ratio is: tungsten source: sulfur source or selenium source = 1:

2.

5. The method for preparing tungsten disulfide / tungsten diselenide electrode material according to claim 1, characterized in that, In step two, the interlayer structure includes the interlayer spacing, sheet size, and number of layers.

6. The method for preparing tungsten disulfide / tungsten diselenide electrode material according to claim 1, characterized in that, In step three, the ferromagnetic metal salt solution is any one or more of FeCl3, FeCl2, CoCl2, NiCl2, Fe(NO3)3, Co(NO3)2, or Ni(NO3)2.

7. The application of an electrode material prepared by the method for preparing tungsten disulfide / tungsten diselenide electrode material according to any one of claims 1-6 in the preparation of anode materials for potassium-ion batteries.

Images