Electrochemical method for regulating phase, resistance and magnetism of two-dimensional layered material

Abstract

The invention discloses an electrochemical method for regulating and controlling the phase, resistance and magnetism of a two-dimensional layered material, and belongs to the field of two-dimensional transition metal chalcogenide. The electrochemical method comprises the steps that an electrode system is provided, the electrode system comprises a working electrode and a counter electrode, the working electrode comprises a two-dimensional layered material, the chemical formula of the two-dimensional layered material is MX2, M represents a transition metal element, and X represents a group VI element where a sulfur element is located; providing an electrolyte, wherein the electrolyte is a soluble salt solution containing magnetic transition metal ions; the electrode system is placed in the electrolyte, and under the action of an external electric field, the magnetic transition metal ions are embedded and separated from the two-dimensional layered material, so that the phase, the resistance and the magnetism of the two-dimensional layered material are synergistically regulated and controlled. According to the technology, magnetic transition metal ions are driven by an electric field to be reversibly embedded into and separated from a two-dimensional layered material, so that the phase, the resistance and the magnetism of the two-dimensional layered material are synergistically and dynamically regulated and controlled, and the problems that the traditional external field regulation and control dimension is single, and intrinsic physical property coupling change is difficult to realize are solved. And multi-physical-property combined regulation and control is realized by adjusting an electric field, so that a basis is provided for application of the material in the fields of photoelectric devices, magnetoelectric storage, sensors and the like.

Description

Technical Field

[0001] This invention relates to the field of two-dimensional transition metal chalcogenides, and more particularly to an electrochemical method for controlling the phase, electrical resistance, and magnetism of two-dimensional layered materials. Background Technology

[0002] In recent years, two-dimensional transition metal chalcogenides (TMDs) have become a hot research topic due to their unique layered atomic structure and tunable electronic band structure. Their general chemical formula is MX2, where M represents a transition metal atom (such as Mo, W, Re, etc.) and X represents a chalcogenide atom (such as S, Se, Te). These compounds not only possess thermodynamically stable phases but also a variety of metastable phases. These metastable phases often exhibit electrical and optical properties that differ significantly from the stable phases, attracting considerable attention. Therefore, achieving precise control over their properties and developing methods to induce phase transitions between different crystal phases are particularly important.

[0003] Currently, common methods for controlling the phase transition of TMDs include chemical vapor deposition, elemental doping, ion intercalation, applying stress or electric fields, thermal treatment, and laser / plasma treatment. Among these, ion intercalation involves ion-electron coupling transfer reactions, guest substance transport, and host redox reactions, exhibiting significant regulatory effects on the charge and physicochemical properties of the host material. The effectiveness and flexibility of ion intercalation strategies give them unique advantages in controlling thermal conductivity, light absorption, superconductivity, and magnetic properties. Electrochemical ion intercalation is an electrochemical process in which target ions in an electrolyte are directionally intercalated into the crystal lattice of a solid material under the drive of a potential gradient and an external electric field. This process, centered on electron transfer and chemical bond recombination, not only allows for precise control of the type, quantity, and position of intercalated ions but also directly modulates the crystal and electronic structures of the host material, thereby driving fundamental changes in the material's physicochemical properties. This results in significant changes in important physical properties such as electrical resistance and magnetism, providing an effective approach for the dynamic design and precise control of material properties.

[0004] Existing research indicates that electrochemical ion intercalation strategies can effectively induce structural phase transitions in materials, enabling single-dimensional control of their electrical or magnetic properties. For example, electrochemical methods can be used to intercalate Li... + Embedded into the MoS2 layers, each Li + An electron is injected into the conduction band of MoS2, achieving efficient n-type heavy doping. This process induces the transformation of MoS2 from a semiconductor phase to a metallic phase, significantly reducing the contact resistance between the metal and semiconductor and improving the performance of MoS2 transistors. Furthermore, the electric field drives H... + Embedded in the TiO2 lattice, it can generate oxygen vacancies and Ti 3+Local magnetic moments are generated, and long-range ferromagnetic coupling is produced through conduction electrons or vacancy media, thus enabling non-magnetic TiO2 to exhibit room-temperature ferromagnetism.

[0005] However, there are still no systematic reports on how to achieve synergistic dynamic control of material phase, resistance, and magnetism based on electrochemical ion intercalation strategies. Achieving synergistic control of conductivity and magnetic response during this process through this strategy holds promise for constructing a novel "electromagnetic dual-channel" sensing and "multimodal weighting" control mechanism, opening new avenues for developing novel multifunctional devices. Therefore, developing such a method capable of jointly controlling multiple properties through a single field drive has significant research and application value for promoting the development of multifunctional materials. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide an electrochemical ion intercalation technology based on magnetic energetic ions. This technology reversibly intercalates and extracts magnetic transition metal ions into and out of TMDs materials via electro-driven processes, thereby synergistically and dynamically controlling their phase, resistance, and magnetism. It aims to solve the problem of traditional external field control having a single dimension and difficulty in achieving coupled changes in intrinsic properties. By adjusting the electric field, multiple properties can be jointly controlled, providing a foundation for the application of such materials in optoelectronic devices, magnetoelectric storage, and sensors.

[0007] The technical solution of the present invention is as follows: An electrochemical method for controlling the phase, electrical resistance, and magnetism of a two-dimensional layered material, comprising the steps of: An electrode system is provided, the electrode system including a working electrode and a counter electrode, the working electrode including a two-dimensional layered material, the two-dimensional layered material having the chemical formula MX2, where M represents a transition metal element and X represents a group VI element to which sulfur belongs; An electrolyte is provided, wherein the electrolyte is a soluble salt solution containing magnetic transition metal ions; The electrode system is placed in the electrolyte, and under the action of an external electric field, the magnetic transition metal ions are inserted and extracted in the two-dimensional layered material, thereby achieving synergistic control of the phase, resistance and magnetism of the two-dimensional layered material.

[0008] This invention achieves controllable phase transitions and electronic doping between semiconductor and metallic states in two-dimensional layered materials such as MoTe2 by controlling the reversible insertion and extraction of magnetic transition metal ions. This allows for reversible switching of conductivity between high and low resistance states. The process involves ion insertion inducing a low-resistivity state (high conductivity) and ion extraction restoring a high-resistivity state (low conductivity). By controlling the ion concentration and interfacial charge transfer behavior, the material is endowed with non-volatility and electrically programmable properties. This characteristic provides an important material and device foundation for reconfigurable electronic switches, tunable resistor networks, radio frequency switches, and topological quantum devices.

[0009] Furthermore, this invention utilizes electrochemically embedded magnetic transition metal ions as a source of local magnetic moments, which can significantly enhance and effectively control the magnetic response of two-dimensional layered materials. The embedded ions can penetrate deep into the bulk phase of the material, achieving deep magnetic control; the embedded state is non-volatile, maintaining its magnetic state without an external field; the magnetic state can be changed simply by driving ion migration with a low-voltage pulse, eliminating the need for a maintenance current and significantly reducing energy consumption. These characteristics make this technology highly promising for applications in high-efficiency electrically controlled magnetic devices and non-volatile magnetic random access memories, providing a feasible technical path for the development of next-generation low-power magnetoelectric storage and logic devices.

[0010] Furthermore, this invention synchronously modulates the electrical and magnetic signals of two-dimensional layered materials through electrochemical ion embedding technology, integrating three functions: dual-channel sensing, multimodal weighting, and in-situ state indication. This provides key technical support for applications such as intelligent sensing in complex environments, highly biomimetic neuromorphic computing, and real-time diagnosis and management of battery state of charge.

[0011] Optionally, an electric field can be applied using the cyclic voltammetry method or the constant current charge-discharge method.

[0012] Optionally, M is one or more of molybdenum, tungsten, rhenium, niobium, tantalum, titanium, and zirconium, and X is one or more of selenium, sulfur, and tellurium.

[0013] Optionally, MX2 is one or more of MoS2, MoTe2, WSe2, and TaTe2.

[0014] Optionally, the method for preparing the working electrode includes the following steps: The two-dimensional layered material and binder are mixed, a solvent is added, and then the mixture is ground to form a slurry. The prepared slurry is coated onto the surface of a conductive substrate and then dried under vacuum to form the working electrode.

[0015] Optionally, the conductive substrate includes one of carbon cloth, glassy carbon, carbon paper, nickel mesh, titanium mesh, copper foil, nickel foam, iron foam, indium tin oxide glass, fluorine-doped SnO2 glass, and aluminum-doped ZnO glass; The adhesive includes one of polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl alcohol, sodium carboxymethyl cellulose, and styrene-butadiene rubber latex; The two-dimensional layered material and the binder are mixed at a mass ratio of (7-9):(3-1).

[0016] Optionally, the magnetic transition metal ion is Mn. 2+ Fe 2+ Fe 3+ Co 2+ Ni 2+ Cr3+ and V 2+ One of them; The electrolyte is one of the following: a sulfate solution containing magnetic transition metal ions, a chloride solution containing magnetic transition metal ions, a nitrate solution containing magnetic transition metal ions, a perchlorate solution containing magnetic transition metal ions, and an acetate solution containing magnetic transition metal ions.

[0017] Optionally, the electrolyte is one of manganese sulfate solution, nickel sulfate solution, ferrous sulfate solution, ferric sulfate solution, nickel chloride solution, manganese chloride solution, cobalt nitrate solution, manganese nitrate solution, manganese acetate solution, and manganese trifluoromethanesulfonate solution.

[0018] Optionally, the concentration of magnetic transition metal ions in the electrolyte is 0.1–5.0 mol / L; The pH value of the electrolyte is 0-6.0.

[0019] Optionally, the counter electrode is one of activated carbon, graphene, platinum sheet, platinum mesh, platinum wire, gold sheet, and graphite electrode; The electrode system also includes a reference electrode, which is one of a silver / silver chloride electrode, a calomel electrode, and a mercury / mercurous sulfate electrode.

[0020] Beneficial effects: (1) This invention utilizes the high sensitivity of the magnetic transition metal ion intercalation process to the local chemical and physical environment to achieve synchronous modulation of electrical signals (such as resistance and impedance) and magnetic signals (such as magnetic susceptibility) of two-dimensional layered materials, thereby constructing a unique "electric-magnetic dual-channel" readout mechanism. This mechanism combines the advantages of high sensitivity and fast response of electrical signals with the strong anti-interference ability and "fingerprint" characteristics of magnetic signals that can reflect the intrinsic state of materials, which can significantly improve the resolution, reliability and information acquisition dimension of the sensor in complex environments.

[0021] (2) By controlling the amount of charge injected by magnetic transition metal ions, this invention can achieve continuous and precise adjustment of the device's conductivity, thereby accurately simulating the weight changes of biological synapses. On this basis, the synergistic correlation between conductivity changes and material magnetic response further forms a "multimodal weight" control mechanism that links electrical and magnetic signals, providing a new path for developing high-performance, highly biomimetic neuromorphic computing devices.

[0022] (3) This invention utilizes the significant abrupt changes in conductivity and magnetic response signals caused by the insertion / extraction of magnetic transition metal ions in two-dimensional layered materials, enabling the material itself to possess in-situ state indication function. By monitoring changes in electrode resistance or magnetic signals in real time, the state of charge and health status of energy storage devices can be directly and accurately reflected, thus providing an effective material basis and detection method for real-time diagnosis and intelligent management of the internal state of batteries. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of an in-situ electrochemical ion intercalation strategy.

[0024] Figure 2 Cyclic voltammetry and constant current charge-discharge curves for electrochemical ion intercalation.

[0025] Figure 3 The image shows the AC impedance diagram of Example 1 (the left side is the Nyquist plot, and the right side is the Bode plot).

[0026] Figure 4 This is the hysteresis loop diagram of Example 1.

[0027] Figure 5 This is the AC impedance diagram for Example 2.

[0028] Figure 6 This is the AC impedance diagram for Comparative Example 1.

[0029] Figure 7 The diagram shows the AC impedance of Comparative Example 2. Detailed Implementation

[0030] This invention provides an electrochemical method for controlling the phase composition, electrical resistance, and magnetism of two-dimensional layered materials. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0031] This invention provides an electrochemical method for controlling the phase, electrical resistance, and magnetism of two-dimensional layered materials, comprising the following steps: An electrode system is provided, the electrode system including a working electrode and a counter electrode, the working electrode including a two-dimensional layered material, the two-dimensional layered material having the chemical formula MX2, where M represents a transition metal element and X represents a group VI element to which sulfur belongs; An electrolyte is provided, wherein the electrolyte is a soluble salt solution containing magnetic transition metal ions; The electrode system is placed in the electrolyte, and under the action of an external electric field, the magnetic transition metal ions are inserted and extracted in the two-dimensional layered material, thereby achieving synergistic dynamic control of the phase, resistance and magnetism of the two-dimensional layered material.

[0032] After fabricating a two-dimensional layered material into a working electrode, it is used to construct a two-electrode system together with a counter electrode, or a three-electrode system together with a counter electrode and a reference electrode. The two-electrode system or the three-electrode system is then placed in an electrolyte containing magnetic transition metal ions. Under the action of an external electric field (which can be achieved through cyclic voltammetry or constant current charge-discharge treatment in the electrolyte containing magnetic transition metal ions), the magnetic transition metal ions are controllably inserted into or extracted from the two-dimensional layered material. The reaction process is as follows: Figure 1 (Shown as a three-electrode system).

[0033] During cyclic voltammetry, applying a reduction potential drives magnetic transition metal ions in the electrolyte to intercalate into the interlayer of a two-dimensional layered material. This process is accompanied by electron transfer into the material bulk, thereby initiating a dynamic evolution of its chemical composition and crystal structure. Subsequently, at an oxidation potential, the magnetic transition metal ions reversibly extract from the interlayer of the two-dimensional layered material and return to the electrolyte. Furthermore, cyclic operation within a set potential window using a constant current charge-discharge method can also control the ion intercalation and extraction behavior. During charging, magnetic transition metal ions in the electrolyte intercalate into the two-dimensional layered material; during discharging, they extract from the two-dimensional layered material.

[0034] The reversible insertion and extraction process of magnetic transition metal ions in two-dimensional layered materials can simultaneously induce three interrelated physical effects: First, the insertion and extraction of magnetic transition metal ions involves charge transfer between the two-dimensional layered material host and the inserted ions, thereby triggering a reversible phase transition in the oxidation state and chemical structure of the two-dimensional layered material, such as the transformation from the semiconductor 2H phase to the metallic 1T or 1T' phase; Second, the inserted ions can act as effective carrier dopants, significantly regulating the carrier concentration and mobility of the two-dimensional layered material, and thus greatly modulating its conductivity; At the same time, the introduced magnetic transition metal ions not only provide local magnetic moments, but can also undergo indirect coupling through conduction electrons, thereby inducing the formation of long-range magnetic order. In one embodiment, the two-dimensional layered material is a two-dimensional transition metal chalcogenide (TMD) compound. The basic chemical formula of the TMD compound is MX2, where M represents a transition metal element located in the d-block of the periodic table, commonly including molybdenum (Mo), tungsten (W), rhenium (Re), niobium (Nb), tantalum (Ta), titanium (Ti), zirconium (Zr), etc., and X represents a group VI element, mainly including selenium (Se), sulfur (S), tellurium (Te), etc. For example, MX2 includes molybdenum disulfide (MoS2), molybdenum ditelluride (MoTe2), tungsten diselenide (WSe2), tantalum ditelluride (TaTe2), etc.

[0035] In one embodiment, the method for preparing the working electrode includes the following steps: The two-dimensional layered material and the binder (such as PVDF) are uniformly mixed at a mass ratio of (7-9):(3-1) (such as 7:3, 8:2, 9:1, etc.), and a solvent such as N-methylpyrrolidone (NMP) is added and then ground to form a slurry. The prepared slurry is uniformly coated onto the surface of a conductive substrate and then dried under vacuum to form the working electrode.

[0036] The aforementioned conductive substrates include, but are not limited to, carbon cloth, glassy carbon, carbon paper, nickel mesh, titanium mesh, copper foil, nickel foam, iron foam, indium tin oxide glass, fluorine-doped SnO2 glass, and aluminum-doped ZnO glass. The aforementioned binders include, but are not limited to, polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl alcohol, sodium carboxymethyl cellulose, and styrene-butadiene rubber latex.

[0037] In one embodiment, the magnetic transition metal ion is a transition metal ion containing unpaired electrons, such as Mn. 2+ Fe 2+ Fe 3+ Co 2+ Ni 2+ Cr 3+ V 2+ The electrolyte is a soluble salt solution containing magnetic transition metal ions (using water as a solvent), including but not limited to the corresponding sulfates, chlorides, nitrates, perchlorates, and acetates, such as manganese sulfate, nickel sulfate, ferrous sulfate, ferric sulfate, nickel chloride, manganese chloride, cobalt nitrate, manganese nitrate, manganese acetate, and manganese trifluoromethanesulfonate.

[0038] In one embodiment, the concentration of magnetic transition metal ions in the electrolyte is 0.1–5.0 mol / L, such as 0.1 mol / L, 0.5 mol / L, 1.0 mol / L, 1.5 mol / L, 2.0 mol / L, 2.5 mol / L, 3.0 mol / L, 3.5 mol / L, 4.0 mol / L, 4.5 mol / L, 5.0 mol / L, etc.

[0039] This concentration range ensures that the electrolyte possesses suitable ionic conductivity and chemical stability, thereby optimizing the kinetics and cycling performance of the electrochemical ion intercalation process. By precisely controlling the concentration of magnetic transition metal ions, the ionic conductivity of the electrolyte can be effectively adjusted, ion transport kinetics optimized, intercalation / extraction rates improved, and quantitative and precise control of the intercalation amount achieved.

[0040] In one embodiment, the pH value of the electrolyte is 0-6.0, such as 0, 1, 2, 3, 4, 5, 6, etc. By precisely controlling the pH value of the electrolyte, the existing form of ions in the solution and the charge state of the electrode surface can be effectively controlled, thereby optimizing the charge transfer impedance and reaction kinetics at the electrode / electrolyte interface. This plays a crucial role in realizing the reversible insertion and extraction of magnetic ions and maintaining the structural stability of the material.

[0041] In one embodiment, the counter electrode is activated carbon, graphene, platinum sheet, platinum mesh, platinum wire, gold sheet, or graphite electrode, etc.

[0042] In one embodiment, the reference electrode is a silver / silver chloride reference electrode, a calomel electrode, or a mercury / mercurous sulfate electrode, etc.

[0043] The present invention will be further described below through specific embodiments.

[0044] Example 1: A MoTe2-CC working electrode was prepared using MoTe2 as the main material and carbon cloth as the conductive substrate. A three-electrode system was constructed using the MoTe2-CC working electrode, a silver / silver chloride reference electrode, and an activated carbon counter electrode. Cyclic voltammetry or constant current charge-discharge treatment was performed in a saturated MnCl2 solution. Figure 2 ), implemented Mn 2+ Controlled insertion and extraction in MoTe2 material. Subsequently, AC impedance and hysteresis loop tests were performed on the resulting system.

[0045] Preparation of working electrode: (1) Using carbon cloth as the conductive current collector, clean its surface with anhydrous ethanol, and perform surface hydrophilic treatment on the carbon cloth with 30% hydrogen peroxide to obtain a hydrophilic carbon cloth current collector. (2) Mix MoTe2 powder and binder PVDF uniformly at a mass ratio of 8:2, and then add N-methylpyrrolidone (NMP) solvent to grind and stir thoroughly to obtain a slurry for later use. (3) Coat the prepared slurry uniformly on the surface of the hydrophilic carbon cloth current collector and place it on a 60 ℃ heating platform to slowly evaporate the NMP solvent. Then, transfer it to a vacuum oven for drying treatment at a baking temperature of 100 ℃ for 24 h to obtain the working electrode.

[0046] Electrode preparation: (1) Using carbon cloth as the conductive current collector, its surface was cleaned with anhydrous ethanol, and the surface of the carbon cloth was hydrophilically treated with 30% hydrogen peroxide to obtain a hydrophilic carbon cloth current collector. (2) Activated carbon powder and binder PVDF were mixed uniformly at a mass ratio of 8:2, and then N-methylpyrrolidone (NMP) solvent was added and thoroughly ground and stirred to obtain a slurry for later use. (3) The prepared slurry was uniformly coated on the surface of the hydrophilic carbon cloth current collector and placed on a 60 ℃ heating platform to slowly evaporate the NMP solvent. Then, it was transferred to a vacuum oven for drying at a baking temperature of 100 ℃ for 24 h to obtain an activated carbon counter electrode.

[0047] Cyclic voltammetry: (1) Add a certain amount of MnCl2 to deionized water, and then stir thoroughly to dissolve until a saturated solution is formed, thus preparing a saturated MnCl2 electrolyte. (2) Immerse the working electrode and the counter electrode completely in the electrolyte, and use vacuum degassing to remove adsorbed gas on the electrodes to improve the contact between the solution and the electrode surface. (3) Place the working electrode, silver / silver chloride reference electrode, and activated carbon counter electrode in sequence, and add saturated MnCl2 electrolyte solution. Cyclic voltammetry is used in the voltage range of 0.78 V to -0.65 V (relative to the silver / silver chloride reference electrode) at 5 mVs. -1 The scan rate was tested, and the results showed a complete set of redox peaks, with the reduction peak corresponding to Mn. 2+ During the embedding of MoTe2, the oxidation peak corresponds to Mn. 2+ The extraction process. Specifically, when the voltage is scanned negatively from 0.78 V to -0.65 V, Mn 2+ Gradually embedded in MoTe2 material and reaching full embedding near -0.65 V, forming Mn x MoTe2; then the voltage was positively flipped back to 0.78V, Mn 2+ Extraction from MoTe2 material restores the structure to its deintercalated state. Alternatively, ion intercalation / deintercalation can also be achieved by charging and discharging within the aforementioned potential range using a constant current charge-discharge method. With an initial voltage of 0.78 V and a cutoff voltage of -0.65 V (relative to a silver / silver chloride reference electrode), during charging, Mn... 2+ Gradually embedded in MoTe2 material; during discharge, Mn 2+ Gradually extracted from the MoTe2 material. In the above process, 0.78 V, -0.65 V, and the return to 0.78 V correspond to "Mn" respectively. 2+ Escape-1", "Mn 2+ "Embedded" and "Mn" 2+ The three characteristic electrochemical states are "de-2".

[0048] Resistance and magnetism tests: (1) At 0.78 V, -0.65 V, and 0.78 V, Mn 2+ EIS testing was performed at the characteristic potentials of embedding and extraction, and the test results are as follows: Figure 3 As shown: In a saturated MnCl2 electrolyte, as Mn... 2+ Embedding MoTe2 material reduces the semicircular diameter of the Nyquist plot, while the peaks in the Bode plot become significantly wider, and the characteristic frequency corresponding to the maximum phase angle shifts to lower frequencies, indicating a decrease in interfacial charge transfer resistance and a longer relaxation time. In subsequent Mn... 2+ During the extraction process, the Nyquist plot and Bode phase diagram described above can be restored to near their initial states, indicating that the process has good electrochemical reversibility. The equivalent circuit model shown in Table 1 is used to... Figure 3 The AC impedance spectroscopy was fitted and analyzed. The results show that the solution resistance of the electrolyte remains stable, while the charge transfer resistance of the electrode material changes significantly. In Mn... 2+ The charge transfer resistance was 103.6 Ω upon extraction, decreased significantly to 5.2 Ω after insertion, and then rebounded to 119.1 Ω upon extraction again. (In Mn) 2+ During the insertion and extraction processes, the insertion state corresponds to a low-resistance state, while the extraction state corresponds to a relatively high-resistance state, and the resistance difference between the two further increases. This result indicates that by controlling Mn... 2+ The embedding / extraction process can effectively adjust the resistivity of the material.

[0049] Table 1. Used for fitting Figure 3 Equivalent circuit model of AC impedance data and comparison data of various resistance parameters obtained

[0050] (2) At 0.78 V, -0.65 V, and 0.78 V, Mn 2+ Hysteresis loop tests were performed at the characteristic potentials of embedding and extraction, and the test results are as follows: Figure 4 As shown: In Mn 2+ Upon extraction, the material exhibits ferromagnetism, but with low saturation magnetic induction; Mn 2+ After embedding, its saturation magnetic induction intensity increases significantly, indicating that the magnetization ability of the material is enhanced under a strong magnetic field, and its ferromagnetism is improved; while Mn 2+ After the second extraction, the magnetism of the material weakened significantly, and the saturation magnetic induction was lower than that in the initial extraction state. This result indicates that the embedding of Mn into MoTe2... 2+ A strong local magnetic moment was introduced and the electronic correlation effect of the system was enhanced, thereby inducing a magnetically ordered phase transition in the material. This was achieved by controlling the Mn... 2+ The amount of embedding can reversibly adjust the magnetic properties of the material to a certain extent, thereby achieving active control over its magnetism.

[0051] Example 1 illustrates that the reversible insertion-extraction of magnetic ions in two-dimensional transition metal chalcogenides can effectively control the phase structure, electrical resistance, and magnetism of the material. Moreover, these different dimensions of control effects are not independent of each other, but exhibit a significant synergistic coupling relationship.

[0052] Example 2: A MoTe2-CC working electrode was prepared using MoTe2 as the main material and carbon cloth as the conductive substrate. A three-electrode system was constructed using the MoTe2-CC working electrode, a silver / silver chloride reference electrode, and an activated carbon counter electrode. Cyclic voltammetry was performed in a 0.5 mol / L MnSO4 electrolyte solution to obtain Mn... 2+ Controllable insertion and extraction were performed in MoTe2 materials, and the system was tested by EIS.

[0053] Preparation of working electrode: (1) Using carbon cloth as the conductive current collector, clean its surface with anhydrous ethanol, and perform surface hydrophilic treatment on the carbon cloth with 30% hydrogen peroxide to obtain a hydrophilic carbon cloth current collector. (2) Mix MoTe2 powder and binder PVDF uniformly at a mass ratio of 8:2, and then add N-methylpyrrolidone (NMP) solvent to grind and stir thoroughly to obtain a slurry for later use. (3) Coat the prepared slurry uniformly on the surface of the hydrophilic carbon cloth current collector and place it on a 60 ℃ heating stage to slowly evaporate the NMP solvent. Then, transfer it to a vacuum oven for drying treatment at a baking temperature of 100 ℃ for 24 h to obtain the working electrode.

[0054] Electrode preparation: (1) Using carbon cloth as the conductive current collector, its surface was cleaned with anhydrous ethanol, and the surface of the carbon cloth was hydrophilically treated with 30% hydrogen peroxide to obtain a hydrophilic carbon cloth current collector. (2) Activated carbon powder and binder PVDF were mixed uniformly at a mass ratio of 8:2, and then N-methylpyrrolidone (NMP) solvent was added and thoroughly ground and stirred to obtain a slurry for later use. (3) The prepared slurry was uniformly coated on the surface of the hydrophilic carbon cloth current collector and placed on a 60 ℃ heating platform to slowly evaporate the NMP solvent. Then, it was transferred to a vacuum oven for drying at a baking temperature of 100 ℃ for 24 h to obtain an activated carbon counter electrode.

[0055] Cyclic voltammetry and EIS testing: (1) Add a certain amount of MnSO4 to deionized water, and then stir thoroughly to dissolve and prepare a 0.5 mol / L MnSO4 electrolyte. (2) Immerse the working electrode and the counter electrode completely in the electrolyte, and use vacuum degassing to remove the adsorbed gas on the electrode to improve the contact between the solution and the electrode surface. (3) Place the working electrode, silver / silver chloride reference electrode and activated carbon counter electrode in sequence, and add 0.5 mol / L MnSO4 electrolyte solution. Cyclic voltammetry is used in the voltage range of 0.7V to -0.8V (relative to the silver / silver chloride reference electrode) at 5mVs. -1 The scan rate was tested, and the results showed a complete set of redox peaks, with the reduction peak corresponding to Mn. 2+ During the embedding of MoTe2, the oxidation peak corresponds to Mn. 2+ The extraction process. Specifically, when the voltage is scanned from 0.7 V negatively to -0.8 V, Mn 2+ Gradually embedded in MoTe2 material and reaching full embedding near -0.8 V, forming Mn x MoTe2; then the voltage is positively swept back to 0.7V, Mn 2+ The material is extracted from MoTe2, and the structure returns to its deintercalated state. During this process, 0.7 V, -0.8 V, and the subsequent return to 0.7 V correspond to "Mn 2+ Escape-1", "Mn 2+ "Embedded" and "Mn" 2+ The three characteristic electrochemical states of "-2" were extracted, and EIS tests were performed at these three characteristic potentials. The results are as follows: Figure 5 As shown: with Mn 2+ Embedding MoTe2 results in a reduction in the semicircular arc of its Nyquist plot; simultaneously, the relaxation peak in the Bode phase diagram broadens, and the characteristic frequency of the maximum phase angle shifts to lower frequencies. In subsequent Mn²... + During the extraction process, the semicircular arcs and peak shapes and positions of the phase angles in the Nyquist plot can be restored to near their initial state. In low-concentration MnSO4 electrolytes, Mn... 2+ The trends of the Nyquist plot and Bode phase diagram during insertion and extraction in MoTe2 material are consistent with the results of Example 1.

[0056] Comparative Example 1: A MoTe2-CC working electrode was prepared using MoTe2 as the main material and carbon cloth as the conductive substrate. A three-electrode system was constructed using the MoTe2-CC working electrode, a silver / silver chloride reference electrode, and an activated carbon counter electrode. Cyclic voltammetry was performed in a 0.5 mol / L H2SO4 electrolyte. + It can be controllably embedded into MoTe2 and tested using EIS.

[0057] Preparation of working electrode: (1) Using carbon cloth as the conductive current collector, clean its surface with anhydrous ethanol, and perform surface hydrophilic treatment on the carbon cloth with 30% hydrogen peroxide to obtain a hydrophilic carbon cloth current collector. (2) Mix MoTe2 powder and binder PVDF uniformly at a mass ratio of 8:2, and then add N-methylpyrrolidone (NMP) solvent to grind and stir thoroughly to obtain a slurry for later use. (3) Coat the prepared slurry uniformly on the surface of the hydrophilic carbon cloth current collector and place it on a 60 ℃ heating stage to slowly evaporate the NMP solvent. Then, transfer it to a vacuum oven for drying treatment at a baking temperature of 100 ℃ for 24 h to obtain the working electrode.

[0058] Electrode preparation: (1) Using carbon cloth as the conductive current collector, its surface was cleaned with anhydrous ethanol, and the surface of the carbon cloth was hydrophilically treated with 30% hydrogen peroxide to obtain a hydrophilic carbon cloth current collector. (2) Activated carbon powder and binder PVDF were mixed uniformly at a mass ratio of 8:2, and then N-methylpyrrolidone (NMP) solvent was added and thoroughly ground and stirred to obtain a slurry for later use. (3) The prepared slurry was uniformly coated on the surface of the hydrophilic carbon cloth current collector and placed on a 60 ℃ heating platform to slowly evaporate the NMP solvent. Then, it was transferred to a vacuum oven for drying at a baking temperature of 100 ℃ for 24 h to obtain an activated carbon counter electrode.

[0059] Cyclic voltammetry and EIS testing: (1) Dilute concentrated sulfuric acid to obtain a 0.5 mol / L H2SO4 electrolyte. (2) Immerse the working electrode and counter electrode completely in the electrolyte and remove adsorbed gas on the electrodes using vacuum degassing to improve the contact between the solution and the electrode surface. (3) Place the working electrode, silver / silver chloride reference electrode and activated carbon counter electrode in sequence, and add 0.5 mol / L H2SO4 electrolyte. Cyclic voltammetry is used in the voltage range of 0.7 V to -0.3 V (relative to the silver / silver chloride reference electrode) at 5 mVs. -1 The scan rate was tested, and the results showed a complete set of redox peaks, with the reduction peak corresponding to H. + During the embedding of MoTe2, the oxidation peak corresponds to H. + The extraction process. Specifically, when the voltage is scanned from 0.7 V negatively to -0.3 V, H... + The MoTe2 material was gradually embedded and reached full embedding near -0.3 V; subsequently, the voltage was positively swept back to 0.7 V, H + The material is extracted, and the structure returns to its de-intercalated state. In the above process, 0.7 V, -0.3 V, and the returned 0.7 V correspond to "H" respectively. + Escape-1", "H +"Embedded" and "H" + The three characteristic electrochemical states of "-2" were extracted, and EIS tests were performed at these three characteristic potentials. The test results are as follows: Figure 6 As shown: H + During the insertion and extraction process of MoTe2 material, its Nyquist plot and Bode phase diagram show no significant changes.

[0060] Comparative Example 2: A MoTe2-CC working electrode was prepared using MoTe2 as the main material and carbon cloth as the conductive substrate. A three-electrode system was constructed using the MoTe2-CC working electrode, a silver / silver chloride reference electrode, and an activated carbon counter electrode. Cyclic voltammetry was performed in a 0.5 mol / L Li2SO4 electrolyte to control the Li... + Controllable insertion and extraction were performed in MoTe2; and the system was tested using EIS.

[0061] Preparation of working electrode: (1) Using carbon cloth as the conductive current collector, clean its surface with anhydrous ethanol, and perform surface hydrophilic treatment on the carbon cloth with 30% hydrogen peroxide to obtain a hydrophilic carbon cloth current collector. (2) Mix MoTe2 powder and binder PVDF uniformly at a mass ratio of 8:2, and then add N-methylpyrrolidone (NMP) solvent to grind and stir thoroughly to obtain a slurry for later use. (3) Coat the prepared slurry uniformly on the surface of the hydrophilic carbon cloth current collector and place it on a 60 ℃ heating stage to slowly evaporate the NMP solvent. Then, transfer it to a vacuum oven for drying treatment at a baking temperature of 100 ℃ for 24 h to obtain the working electrode.

[0062] Electrode preparation: (1) Using carbon cloth as the conductive current collector, its surface was cleaned with anhydrous ethanol, and the surface of the carbon cloth was hydrophilically treated with 30% hydrogen peroxide to obtain a hydrophilic carbon cloth current collector. (2) Activated carbon powder and binder PVDF were mixed uniformly at a mass ratio of 8:2, and then N-methylpyrrolidone (NMP) solvent was added and thoroughly ground and stirred to obtain a slurry for later use. (3) The prepared slurry was uniformly coated on the surface of the hydrophilic carbon cloth current collector and placed on a 60 ℃ heating platform to slowly evaporate the NMP solvent. Then, it was transferred to a vacuum oven for drying at a baking temperature of 100 ℃ for 24 h to obtain an activated carbon counter electrode.

[0063] Cyclic voltammetry and EIS testing: (1) Add a certain amount of Li2SO4 to deionized water, and then stir thoroughly to dissolve and prepare a 0.5 mol / L Li2SO4 electrolyte. (2) Immerse the working electrode and the counter electrode completely in the electrolyte, and use vacuum degassing to remove the adsorbed gas on the electrode to improve the contact between the solution and the electrode surface. (3) Place the working electrode, silver / silver chloride reference electrode and activated carbon counter electrode in sequence, and add 0.5 mol / L Li2SO4 electrolyte solution. Cyclic voltammetry is used in the voltage range of 0.9 V to -0.9 V (relative to the silver / silver chloride reference electrode) at 5 mVs. -1 The scan rate was tested, and the results showed a complete set of redox peaks, with the reduction peak corresponding to Li. + During the embedding of MoTe2, the oxidation peak corresponds to Li. + The extraction process. Specifically, when the voltage is scanned from 0.9 V negatively to -0.9 V, Li + The Li-Te2 material was gradually embedded and reached full embedding near -0.9 V; subsequently, the voltage was positively swept back to 0.9 V. + The material is extracted, and the structure returns to its deintercalated state. In the above process, 0.9 V, -0.9 V, and the returned 0.9 V correspond to "Li + Escape-1", "Li + "Embedded" and "Li" + The three characteristic electrochemical states of "-2" were extracted, and EIS tests were performed at these three characteristic potentials. The results are as follows: Figure 7 As shown: Li + During the insertion and extraction process of MoTe2 material, its Nyquist plot and Bode phase diagram show no significant changes.

[0064] Figure 6 and Figure 7 Displayed in H + and Li + During the insertion and extraction process of MoTe2 materials, neither its Nyquist plot nor its Bode phase diagram showed significant changes. This result indicates that nonmetallic ions (such as H+) can significantly alter the intercalation and extraction process. + ) and non-magnetic metal ions (such as Li) + The insertion and extraction of ions have little impact on the resistivity and interfacial transport kinetics of this material. This is especially true with magnetic metal ions (such as Mn). 2+ Compared to the significant resistance change caused by embedding, the electrochemical behavior of non-metallic ions and non-magnetic metal ions in MoTe2 is more reversible and has a weaker impact on the electrical properties of the material.

[0065] In summary, this invention provides an electrochemical method for controlling the phase, resistance, and magnetism of two-dimensional layered materials. By controlling the reversible insertion and extraction of magnetic transition metal ions in two-dimensional layered materials such as MoTe2, this invention achieves a controllable phase transition and electronic doping between the semiconductor and metallic states of the two-dimensional layered materials, thereby enabling reversible switching of conductivity between high and low resistance states. This process induces a low-resistivity state (high conductivity) through ion insertion and restores a high-resistivity state (low conductivity) through ion extraction. By controlling the ion concentration and interfacial charge transfer behavior, the material is endowed with non-volatility and electrically programmable properties. This characteristic provides an important material and device foundation for reconfigurable electronic switches, tunable resistor networks, radio frequency switches, and topological quantum devices.

[0066] Furthermore, this invention utilizes electrochemically embedded magnetic transition metal ions as a source of local magnetic moments, which can significantly enhance and effectively control the magnetic response of two-dimensional layered materials. The embedded ions can penetrate deep into the bulk phase of the material, achieving deep magnetic control; the embedded state is non-volatile, maintaining its magnetic state without an external field; the magnetic state can be changed simply by driving ion migration with a low-voltage pulse, eliminating the need for a maintenance current and significantly reducing energy consumption. These characteristics make this technology highly promising for applications in high-efficiency electrically controlled magnetic devices and non-volatile magnetic random access memories, providing a feasible technical path for the development of next-generation low-power magnetoelectric storage and logic devices.

[0067] Furthermore, this invention synchronously modulates the electrical and magnetic signals of two-dimensional layered materials through electrochemical ion embedding technology, integrating three functions: dual-channel sensing, multimodal weighting, and in-situ state indication. This provides key technical support for applications such as intelligent sensing in complex environments, highly biomimetic neuromorphic computing, and real-time diagnosis and management of battery state of charge.

[0068] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. An electrochemical method for controlling the phase, electrical resistance, and magnetic properties of a two-dimensional layered material, characterized in that, Including the following steps: An electrode system is provided, the electrode system including a working electrode and a counter electrode, the working electrode including a two-dimensional layered material, the two-dimensional layered material having the chemical formula MX2, where M represents a transition metal element and X represents a group VI element to which sulfur belongs; An electrolyte is provided, wherein the electrolyte is a soluble salt solution containing magnetic transition metal ions; The electrode system is placed in the electrolyte, and under the action of an external electric field, the magnetic transition metal ions are inserted and extracted in the two-dimensional layered material, thereby achieving synergistic control of the phase, resistance and magnetism of the two-dimensional layered material.

2. The electrochemical method for controlling the phase, resistance, and magnetism of two-dimensional layered materials according to claim 1, characterized in that, An electric field is applied using either the cyclic voltammetry method or the constant current charge-discharge method.

3. The electrochemical method for controlling the phase, resistance, and magnetism of two-dimensional layered materials according to claim 1, characterized in that, M is one or more of molybdenum, tungsten, rhenium, niobium, tantalum, titanium, and zirconium, and X is one or more of selenium, sulfur, and tellurium.

4. The electrochemical method for controlling the phase, resistance, and magnetism of two-dimensional layered materials according to claim 3, characterized in that, The MX2 is one or more of MoS2, MoTe2, WSe2, and TaTe2.

5. The electrochemical method for controlling the phase, resistance, and magnetism of two-dimensional layered materials according to claim 1, characterized in that, The method for preparing the working electrode includes the following steps: The two-dimensional layered material and binder are mixed, a solvent is added, and then the mixture is ground to form a slurry. The prepared slurry is coated onto the surface of a conductive substrate and then dried under vacuum to form the working electrode.

6. The electrochemical method for controlling the phase, resistance, and magnetism of two-dimensional layered materials according to claim 5, characterized in that, The conductive substrate includes one of the following: carbon cloth, glassy carbon, carbon paper, nickel mesh, titanium mesh, copper foil, nickel foam, iron foam, indium tin oxide glass, fluorine-doped SnO2 glass, and aluminum-doped ZnO glass. The adhesive includes one of polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl alcohol, sodium carboxymethyl cellulose, and styrene-butadiene rubber latex; The two-dimensional layered material and the binder are mixed at a mass ratio of (7-9):(3-1).

7. The electrochemical method for controlling the phase, resistance, and magnetism of two-dimensional layered materials according to claim 1, characterized in that, The magnetic transition metal ion is Mn. 2+ Fe 2+ Fe 3+ Co 2+ Ni 2+ Cr 3+ and V 2+ One of them; The electrolyte is one of the following: a sulfate solution containing magnetic transition metal ions, a chloride solution containing magnetic transition metal ions, a nitrate solution containing magnetic transition metal ions, a perchlorate solution containing magnetic transition metal ions, and an acetate solution containing magnetic transition metal ions.

8. The electrochemical method for controlling the phase, resistance, and magnetism of two-dimensional layered materials according to claim 7, characterized in that, The electrolyte is one of the following: manganese sulfate solution, nickel sulfate solution, ferrous sulfate solution, ferric sulfate solution, nickel chloride solution, manganese chloride solution, cobalt nitrate solution, manganese nitrate solution, manganese acetate solution, and manganese trifluoromethanesulfonate solution.

9. The electrochemical method for controlling the phase, resistance, and magnetism of two-dimensional layered materials according to claim 1, characterized in that, The concentration of magnetic transition metal ions in the electrolyte is 0.1–5.0 mol / L; The pH value of the electrolyte is 0-6.

0.

10. The electrochemical method for controlling the phase, resistance, and magnetism of two-dimensional layered materials according to claim 1, characterized in that, The counter electrode is one of activated carbon, graphene, platinum sheet, platinum mesh, platinum wire, gold sheet, and graphite electrode; The electrode system also includes a reference electrode, which is one of a silver / silver chloride electrode, a calomel electrode, and a mercury / mercurous sulfate electrode.

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