Iron-selectively-doped molybdenum disulfide / rhenium disulfide heterostructure nanometer conductive material, preparation method and application thereof

Abstract

The application relates to the technical field of electrochemical energy storage materials, in particular to a Fe-selectively-doped MoS2 / ReS2 heterostructure nanometer conductive material, a preparation method and application thereof, and realizes directional doping of iron elements in MoS2 phases through the obtained Fe-MoS2 / ReS2 heterostructure nanometer conductive material, the Fe-MoS2 / ReS2 heterostructure is vertically and uniformly grown on the surface of a conductive carbon fiber fabric, a continuous and uniformly-distributed wrinkle-shaped nanometer sheet-shaped heterostructure is formed, and a three-dimensional nanometer system with a high specific surface area and rich electrochemical active sites is constructed, excellent interface channels are provided for fast charge migration and electrochemical reactions. The introduction of iron elements and the hetero-interface jointly regulate the energy storage performance of the electrode material, and when applied to supercapacitors, the supercapacitors exhibit efficient charge storage, excellent rate performance and good cycle stability.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of electrochemical energy storage materials, in particular to an iron-selectively-doped MoS2 / ReS2 heterostructure nanometer conductive material and a preparation method and application thereof. BACKGROUND

[0002] In the field of electrochemical energy storage, heterostructure electrode materials have become one of the research hotspots for improving the capacitive performance due to the interface synergistic effect and the multi-component synergistic regulation mechanism. Many studies have constructed various heterostructures, such as MoS2 / CoS, MoS2 / NiS2, Ni-MoS2 / Bi2WO6, etc., and realized more excellent electrochemical performance than conventional single-component materials through the electronic structure regulation and interface charge migration between materials. These heterostructures are usually prepared by in-situ growth, chemical vapor deposition, interface self-assembly, etc., and show good prospects in improving the charge storage capacity and enhancing the ion diffusion.

[0003] However, the existing heterostructure materials still have the following significant defects and deficiencies: 1) unstable hetero-interface structure: due to the large lattice mismatch between the two phases, the interface stress is easy to concentrate, which easily leads to delamination or interface fracture, thereby affecting the stability and service life of the electrode. 2) limited electronic transmission efficiency: the existing materials usually do not fully consider the energy level matching and charge migration path of each component, which leads to interface electron accumulation or transmission blockage, limits the effective migration of electrons between interfaces, causes large internal resistance and low conductivity, and affects the rate performance. 3) poor controllability and limited structural precision: the interface, morphology and composition of the heterostructure are often difficult to accurately control, the combination mode between materials is not clear, and the repeatability and controllability are poor. SUMMARY

[0004] The purpose of the present application is to provide an iron-selectively-doped MoS2 / ReS2 heterostructure nanometer conductive material and a preparation method and application thereof, which solve the problems of weak interface bonding force and low active site utilization rate of the existing heterostructure electrode materials.

[0005] To achieve the above-mentioned purpose, the present application provides a preparation method of an iron-selectively-doped MoS2 / ReS2 heterostructure nanometer conductive material, which comprises the following steps,

[0006] S1, cutting a conductive carbon fiber fabric and immersing it in a mixed solution of concentrated nitric acid and concentrated sulfuric acid, ultrasonic treatment after immersion, cleaning and drying to obtain a cleaned conductive carbon fiber fabric;

[0007] S2, adding iron sulfate, ammonium molybdate tetrahydrate, high-rhenium acid ammonium and thiourea into deionized water in sequence, stirring uniformly to obtain a reactant mixed solution;

[0008] In S2, the amount of substance of the ferric sulfate in the reactant mixed solution is 0.001-0.10 mmol / mL, the amount of substance of the ammonium molybdate tetrahydrate is 0.008-0.50 mmol / mL, the amount of substance of the thiourea is 0.1-0.50 mmol / mL, and the amount of substance of the ammonium perrhenate is 0.025-0.10 mmol / mL.

[0009] In S3, the reactant mixed solution obtained in S2 is poured into a polytetrafluoroethylene lining of a reaction kettle, and then the cleaned conductive carbon fiber fabric obtained in S1 is immersed in the reactant mixed solution, and the reaction kettle is sealed.

[0010] In S4, the reaction kettle in S3 is heated, and after heat preservation, it is naturally cooled to room temperature. After the reaction is completed, the sample is taken out, cleaned, vacuum dried, and cooled to room temperature to obtain the Fe-MoS2 / ReS2 heterostructure nanometer conductive material.

[0011] Preferably, in S1, the volume ratio of concentrated nitric acid to concentrated sulfuric acid is 1:2-4, and the soaking time is 24-72 h.

[0012] Preferably, in S1, the ultrasonic treatment time is 0.1-1 h, the ultrasonic treatment is carried out in deionized water, the cleaning is carried out by using deionized water for 2-6 times, and the drying temperature is 50-70°C.

[0013] Preferably, in S2, the stirring speed is 300-500 r / min, and the stirring time is 5-30 min.

[0014] Preferably, in S3, the volume of the reactant mixed solution accounts for 45-80% of the volume of the polytetrafluoroethylene lining, and the cleaned conductive carbon fiber fabric is completely immersed in the reactant mixed solution.

[0015] Preferably, in S4, when heating, the heating rate is 5-10°C / min, and the temperature is heated to 180-200°C, and the heat preservation time is 18-20 h.

[0016] Preferably, in S4, the cleaning is carried out by using deionized water and ethanol alternately for 3-5 times, the drying temperature is 65-75°C, and the drying time is 6-24 h.

[0017] A kind of iron selective doping MoS2 / ReS2 heterostructure nanometer conductive material (Fe-MoS2 / ReS2 heterostructure nanometer conductive material), using the preparation method of the above-mentioned iron selective doping MoS2 / ReS2 heterostructure nanometer conductive material is prepared.

[0018] The application of a kind of iron selective doping MoS2 / ReS2 heterostructure nanometer conductive material, the Fe-MoS2 / ReS2 heterostructure nanometer conductive material described above is applied to the electrode material of supercapacitor.

[0019] The mechanism of the present application is as follows:

[0020] The present application adopts a one-step hydrothermal synthesis process, grows an iron-doped ReS2 / MoS2 heterostructure on the surface of a conductive carbon fiber fabric substrate in a high-temperature and high-pressure hydrothermal reactor through an in-situ growth method, and obtains a Fe-MoS2 / ReS2 heterostructure nanometer conductive material. The material forms a tightly coupled layered heterostructure. The introduction of two-dimensional ReS2 constructs a large number of stable heterojunction interfaces, enhances the interface synergistic effect, is conducive to the separation and transmission of charges at the interface, and suppresses the self-stacking phenomenon of the layered material, thereby improving the ion diffusion efficiency. The two-dimensional ReS2 and MoS2 have high compatibility in crystal structure, interlayer interaction and energy band structure, and the heterostructure formed between the two has good lattice matching and stable interface bonding state. And the van der Waals force assembly method can effectively avoid the structural stress caused by chemical bond mismatch, thereby giving the heterostructure excellent thermodynamic and structural stability.

[0021] The directional doping of iron elements in the MoS2 phase, iron atoms preferentially enter the MoS2 lattice and replace the Mo sites therein, thereby realizing stable and effective doping. Not only does it induce the formation of MoS2 lattice defects and regulate the charge distribution, but also enhances the electronic coupling effect of the MoS2 / ReS2 heterojunction, improves the interface charge transfer rate and structural stability. Through precise regulation of the MoS2 lattice structure and electronic properties, the formation of lattice distortion and defect sites is induced, the number of unsaturated metal active centers is increased, the electronic conductivity is improved, and the interference with the ReS2 phase structure and performance is avoided, thereby maintaining its intrinsic advantages. The effectively stabilized heterostructure interface enhances the electronic coupling effect of the heterojunction interface and the interface charge transfer efficiency, and significantly improves the electronic / ion transport efficiency and structural stability of the material.

[0022] Therefore, the present application adopts the above-mentioned iron-selective-doped MoS2 / ReS2 heterostructure nanometer conductive material, its preparation method and application, which has the following advantages:

[0023] 1. The present application uses a simple one-step hydrothermal method in a high-temperature and high-pressure hydrothermal reactor, uses iron sulfate, molybdate ammonium, high-rhenium acid ammonium and thiourea as iron source, molybdenum source, rhenium source and sulfur source, uses deionized water as reaction solvent, and constructs an iron-doped MoS2 / ReS2 heterostructure on the surface of a conductive carbon fiber fabric substrate through an in-situ growth method. No adhesive is needed, which significantly promotes the uniform distribution of the material and improves the structural stability and active material utilization rate, and is suitable for the preparation of high-performance flexible electrodes.

[0024] 2、The preparation method provided by the application has the advantages of simple process, environmental friendliness, low cost, large yield, no subsequent treatment, high repeatability, uniform and controllable components, and wide application prospect in the field of electrochemical energy storage;

[0025] 3、The Fe-MoS2 / ReS2 heterostructure nanometer conductive material prepared by the application effectively constructs a stable heterostructure interface, the rich heterostructure interface not only provides an efficient channel for electron rapid transmission, but also exposes more active sites through the interface synergistic effect, and significantly promotes the progress of the redox reaction;

[0026] 4、In the application, the iron element is selectively doped in the MoS2 phase, the crystal lattice structure of the MoS2 is stabilized, part of defects is induced, and the electronic coupling effect of the MoS2 / ReS2 heterojunction is enhanced. The obtained Fe-MoS2 / ReS2 heterostructure nanometer conductive material has a high specific surface area and rich active sites, and the flexible electrode prepared from the material shows excellent rate performance and cycle stability when applied to a supercapacitor.

[0027] The technical solutions of the application will be further described in detail below with reference to the drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a SEM combined graph of example 1 and example 2 of the application, wherein, Figure 1 a in is a SEM graph of example 1 under 1 μm, Figure 1 b in is a SEM graph of example 1 under 500 nm, Figure 1 c in is a SEM graph of example 2 under 200 nm;

[0029] Figure 2 is a TEM combined graph of example 1 of the application, wherein, Figure 2 a in is a TEM graph of example 1 under 10 nm, Figure 2 b in is a local enlarged view of the b area in the TEM graph of example 1, Figure 2 c in is a reverse fast Fourier transform graph of the c area in the TEM graph of example 1;

[0030] Figure 3 is an XRD graph of example 1 of the application;

[0031] Figure 4 is an XPS combined graph of example 1 and comparative example 2, wherein, Figure 4 a in is a Mo 3d orbital graph, Figure 4 b in is a Re 4f orbital graph;

[0032] Figure 5is the cyclic voltammogram of the embodiment 1, comparative example 1 and comparative example 2 of the present application at a scanning rate of 20 mV / s;

[0033] Figure 6 is the constant current charge-discharge curve of the embodiment 1, comparative example 1 and comparative example 2 of the present application at a current density of 1 A / g;

[0034] Figure 7 is the constant current charge-discharge curve of the embodiment 1 of the present application at different current densities;

[0035] Figure 8 is the cycle performance graph of the embodiment 1 of the present application. DETAILED DESCRIPTION

[0036] The present application is further described below in conjunction with the accompanying drawings and examples. Unless otherwise defined, technical or scientific terms used in the present application should be understood as having the commonly understood meaning as understood by one of ordinary skill in the art to which the present application pertains. The features mentioned in the present application or the features mentioned in the specific examples can be combined in any manner, and these specific examples are only used to illustrate the present application and are not used to limit the scope of the present application.

[0037] The conductive carbon fiber fabric is of Taiwan Carbon Technology Co., Ltd., and the model number is WOS1009;

[0038] The concentrated nitric acid used is a third-grade reagent, and the concentration is 65-68%;

[0039] The concentrated sulfuric acid is a third-grade reagent, and the concentration is 95-98%;

[0040] The ferric sulfate and thiourea are commercially available analytical pure powder reagents;

[0041] The ammonium molybdate tetrahydrate is a reagent-grade powder reagent;

[0042] The ammonium perrhenate has a purity of ≥99%.

[0043] Example 1

[0044] S1, cut the conductive carbon fiber fabric into 2x4 cm 2 , immerse in a mixed solution of concentrated nitric acid and concentrated sulfuric acid with a volume ratio of 1:3 for 48 h, and then ultrasonically treat in deionized water for 0.5 h after immersion, wash with deionized water for 5 times to remove the residual acid, and dry at 65°C for 12 h to obtain the washed conductive carbon fiber fabric.

[0045] S2, add 0.0350 g of ferric sulfate, 0.6179 g of ammonium molybdate tetrahydrate, 0.4024 g of ammonium perrhenate and 1.0658 g of thiourea into 45 ml of deionized water, and stir at 500 r / min for 15 min to obtain a reaction mixture.

[0046] S3, pour the reaction mixture solution obtained in S2 into a 100 mL polytetrafluoroethylene liner of a reaction kettle, then immerse the cleaned conductive carbon fiber fabric obtained in S1 into the reaction mixture solution, the cleaned conductive carbon fiber fabric is completely immersed in the reaction mixture solution, and the reaction kettle is sealed.

[0047] S4, heat the reaction kettle (high-temperature and high-pressure hydrothermal reaction kettle) in S3 in a precision air blast drying oven, heat to 200°C at a heating rate of 10°C / min, and naturally cool to room temperature after holding for 18 h. The reacted sample is taken out and cleaned with deionized water and 75% ethanol alternately for 3 times, vacuum dried at 65°C for 12 h, and then cooled to room temperature to obtain the Fe-MoS2 / ReS2 heterostructure nanometer conductive material. The Fe-MoS2 / ReS2 heterostructure nanometer conductive material is placed in a vacuum drying oven for storage at room temperature to prevent oxidation.

[0048] Example 2

[0049] S1, cut the conductive carbon fiber fabric into 2×4 cm 2 , immerse in a mixed solution of concentrated nitric acid and concentrated sulfuric acid with a volume ratio of 1:3 for 48 h, and then ultrasonically treat in deionized water for 0.5 h. The cleaned conductive carbon fiber fabric is obtained by washing with deionized water for 5 times and drying at 65°C for 12 h.

[0050] S2, add 0.0350 g of iron sulfate, 0.6179 g of ammonium molybdate tetrahydrate, 0.4024 g of ammonium perrhenate, and 1.0658 g of thiourea into 60 ml of deionized water, and stir at 500 r / min for 15 min to obtain a reaction mixture solution.

[0051] S3, pour the reaction mixture solution obtained in S2 into a 100 mL polytetrafluoroethylene liner of a reaction kettle, then immerse the cleaned conductive carbon fiber fabric obtained in S1 into the reaction mixture solution, the cleaned conductive carbon fiber fabric is completely immersed in the reaction mixture solution, and the reaction kettle is sealed.

[0052] S4, heat the reaction kettle (high-temperature and high-pressure hydrothermal reaction kettle) in S3 in a precision air blast drying oven, heat to 200°C at a heating rate of 10°C / min, and naturally cool to room temperature after holding for 18 h. The reacted sample is taken out and cleaned with deionized water and 75% ethanol alternately for 3 times, vacuum dried at 65°C for 12 h, and then cooled to room temperature to obtain the Fe-MoS2 / ReS2 heterostructure nanometer conductive material. The Fe-MoS2 / ReS2 heterostructure nanometer conductive material is placed in a vacuum drying oven for storage at room temperature to prevent oxidation.

[0053] Comparative Example 1

[0054] S1, cut the conductive carbon fiber fabric into 2 x 4 cm 2 , immerse in the mixed solution of concentrated nitric acid and concentrated sulfuric acid with a volume ratio of 1:3 for 48h, ultrasonic treatment in deionized water for 0.5h after immersion, deionized water cleaning 5 times, drying at 65℃ for 12h to obtain the cleaned conductive carbon fiber fabric.

[0055] S2, add 0.6179g of ammonium molybdate tetrahydrate and 1.0658g of thiourea to 45ml of deionized water, stir at 500r / min for 15min, and obtain a reaction mixture solution.

[0056] S3, pour the reaction mixture solution obtained in S2 into the 100mL polytetrafluoroethylene liner of the reaction kettle, then immerse the cleaned conductive carbon fiber fabric obtained in S1 into the reaction mixture solution, and the cleaned conductive carbon fiber fabric is completely immersed in the reaction mixture solution, and the reaction kettle is sealed.

[0057] S4, heat the reaction kettle in S3 in a precision air drying oven, heat to 200℃ at a heating rate of 10℃ / min, and naturally cool to room temperature after holding for 18h. Take out the reacted sample and clean it with deionized water and 75% ethanol alternately for 3 times, vacuum dry at 65℃ for 12h, and cool to room temperature to obtain the MoS2 heterostructure nano-conductive material.

[0058] Comparative Example 2

[0059] S1, cut the conductive carbon fiber fabric into 2 x 4 cm 2 , immerse in the mixed solution of concentrated nitric acid and concentrated sulfuric acid with a volume ratio of 1:3 for 48h, ultrasonic treatment in deionized water for 0.5h after immersion, deionized water cleaning 5 times, drying at 65℃ for 12h to obtain the cleaned conductive carbon fiber fabric.

[0060] S2, add 0.6179g of ammonium molybdate tetrahydrate, 0.4024g of ammonium perrhenate and 1.0658g of thiourea to 45ml of deionized water, stir at 500r / min for 15min, and obtain a reaction mixture solution.

[0061] S3, pour the reaction mixture solution obtained in S2 into the 100mL polytetrafluoroethylene liner of the reaction kettle, then immerse the cleaned conductive carbon fiber fabric obtained in S1 into the reaction mixture solution, and the cleaned conductive carbon fiber fabric is completely immersed in the reaction mixture solution, and the reaction kettle is sealed.

[0062] S4, the reactor in S3 was heated in a precision air drying oven, heated to 200℃ at a heating rate of 10℃ / min, and naturally cooled to room temperature after holding for 18h. The reacted sample was taken out and cleaned with deionized water and 75% ethanol alternately for 3 times, and then vacuum dried at 65℃ for 12h before cooling to room temperature to obtain the MoS2 / ReS2 heterostructure nanometer conductive material.

[0063] Test Example

[0064] a, SEM test

[0065] The Fe-MoS2 / ReS2 heterostructure nanometer conductive material in Example 1 and Example 2 was subjected to SEM test, and the results are shown in Figure 1 It can be seen that the Fe-MoS2 / ReS2 heterostructure in Example 1 and Example 2 grows vertically and uniformly on the surface of the conductive carbon fiber fabric, forming a continuous and uniformly distributed wrinkle-shaped nanosheet heterostructure, and constructing a three-dimensional nanosystem with high specific surface area and rich electrochemical active sites, wherein the iron element is selectively doped in the MoS2 phase, which is beneficial to the penetration of electrolyte ions and charge transfer. The structural distortion introduced by iron doping further increases the active site density, and improves the electrochemical reaction activity and energy storage performance.

[0066] b, TEM test

[0067] The Fe-MoS2 / ReS2 heterostructure nanometer conductive material in Example 1 was subjected to TEM test, and the results are shown in Figure 2 It can be seen that the Fe-MoS2 / ReS2 heterostructure nanometer conductive material has a layered nanoscale structure, wherein the interlayer spacing of ReS2 and MoS2 crystal faces is 0.677nm (002 crystal face) and 0.663nm (002 crystal face), respectively. In addition, it is observed that there are 1T phase and 2H phase MoS2 in the b region, which clearly confirms the successful phase transition of MoS2 and significantly expands the interlayer spacing. The lattice is continuous and closely combined at the interface, indicating that the heterostructure has good crystallinity and lattice matching, providing excellent interface channels for fast charge migration and electrochemical reaction. At the same time, slight lattice distortion and strain stripes are observed in the local area (white dashed line part), indicating that iron doping introduces stress regulation in the process of hetero-interface formation, which helps to construct more electrochemical active sites, thereby improving the specific capacitance of the material.

[0068] c, XRD test

[0069] The Fe-MoS2 / ReS2 heterostructure nanometer conductive material in Example 1, the MoS2 heterostructure nanometer conductive material in Comparative Example 1, and the MoS2 / ReS2 heterostructure nanometer conductive material in Comparative Example 2 were subjected to XRD test, and the results are shown in Figure 3The comparison can be seen that the three all present typical MoS2 characteristics in the main diffraction peak positions, wherein the peak values of 7.88°, 16.54°, 32.66°, 58.18° in the spectrum of Example 1 correspond to the (002), (004), (100) and (110) crystal planes of MoS2 (JCPDS No. 37-1492) respectively, indicating that MoS2 with 1T phase characteristics is formed in the sample. Further analysis found that compared with Comparative Example 1, new diffraction peaks appeared at 32.66° and 42.82° in Comparative Example 2 and Example 1, which are attributed to the (-201) and (1-31) crystal planes of ReS2 (JCPDS No. 27-0502) respectively, confirming the successful synthesis of the heterostructure.

[0070] In addition, the intensity of the MoS2 related diffraction peaks in Example 1 is obviously lower than that of Comparative Example 1 and Comparative Example 2, and a certain degree of peak shape broadening is presented, which is speculated to be mainly due to the introduction of Fe element which disturbs the crystal structure of MoS2 to a certain extent, which may lead to the decrease of crystallinity or the increase of lattice defects. In addition, it is also observed that the broad diffraction peak at 25.62° is attributed to the (003) plane of the conductive carbon fiber fabric, indicating the existence and structural integrity of the substrate.

[0071] d、XPS test

[0072] The Fe-MoS2 / ReS2 heterostructure nanometer conductive material in Example 1 and the MoS2 / ReS2 heterostructure nanometer conductive material in Comparative Example 2 were subjected to XPS test, and the results are shown in Figure 4 Due to the good spatial fitting of the radius of Fe ion and Mo ion in size, it makes iron more easily doped into the MoS2 crystal structure and occupies the position of Mo, so as to realize stable doping behavior. In contrast, the ReS2 structure is significantly distorted, and the bond angle is relatively complex, which is not conducive to the stable replacement of iron atoms in its lattice, so it can be considered that iron has a stronger tendency to dope in MoS2. Compared with Comparative Example 2, the binding energy of Mo3d orbit in Example 1 is blue-shifted by about 0.1 eV as a whole, indicating that the electronic environment around the Mo atom has changed significantly. The binding energy position of Re 4f orbit has almost no obvious change, which shows that the chemical environment of Re is not disturbed. According to this, it can be inferred that Fe is mainly doped in MoS2 rather than ReS2, thereby confirming the selective doping behavior of iron.

[0073] e、Electrochemical performance test

[0074] The Fe-MoS2 / ReS2heterostructure nanoelectrode material in Example 1, the MoS2heterostructure nanoelectrode material in Comparative Example 1 and the MoS2 / ReS2heterostructure nanoelectrode material in Comparative Example 2 were subjected to cyclic voltammetry test at a scanning rate of 20 mV / s, and the results are shown in Figure 5 .

[0075] It can be seen that the three electrode materials corresponding to Comparative Example 1, Comparative Example 2 and Example 1 all exhibit a nearly rectangular cyclic voltammetry curve morphology, indicating that the electrochemical process thereof is mainly dominated by pseudo-capacitance behavior. Under the same mass loading, the Fe-MoS2 / ReS2heterostructure nanoelectrode material (Example 1) exhibits the largest integral area and higher response current in the entire test voltage range, which has obvious advantages compared with the single MoS2heterostructure nanoelectrode material (Comparative Example 1) and the MoS2 / ReS2heterostructure nanoelectrode material without iron doping (Comparative Example 2). The results show that the introduction of iron element and the heterojunction jointly regulate the energy storage performance of the electrode material.

[0076] The Fe-MoS2 / ReS2heterostructure nanoelectrode material in Example 1, the MoS2heterostructure nanoelectrode material in Comparative Example 1 and the MoS2 / ReS2heterostructure nanoelectrode material in Comparative Example 2 were subjected to discharge test at a current density of 1 A / g, and the results are shown in Figure 6 .

[0077] The Fe-MoS2 / ReS2heterostructure nanoelectrode material (Example 1) exhibits the longest discharge duration, followed by the MoS2 / ReS2heterostructure nanoelectrode material (Comparative Example 2), and the discharge time of the MoS2heterostructure nanoelectrode material (Comparative Example 1) is the shortest. The difference in discharge performance clearly shows that iron doping and heterostructure construction have a significant synergistic gain effect in improving the overall electrochemical performance of the material. Specifically, the heterojunction constructed with ReS2promotes the rapid separation and efficient transmission of charges, thereby significantly enhancing the conductivity and charge transfer kinetics of the electrode material; at the same time, the introduction of iron element further effectively regulates the electronic structure of MoS2, reduces the charge transfer resistance and improves its energy storage capacity.

[0078] The Fe-MoS2 / ReS2heterostructure nanoelectrode material in Example 1 was subjected to charge and discharge test, and the results are shown in Figure 7The charge-discharge curves of the Fe-MoS2 / ReS2 heterostructure nanoelectrically conductive material under different current densities show good symmetry and linear characteristics, indicating that it has excellent electrochemical reversibility and stable pseudocapacitive behavior. With the increase of current density, the charge-discharge time is shortened, but the curve shape remains basically stable, showing excellent rate performance and rapid charge transport capacity of the material.

[0079] The Fe-MoS2 / ReS2 heterostructure nanoelectrically conductive material in Example 1 was tested for cycle stability at a current density of 5 A / g, and the results are shown in Figure 8 The capacity retention rate is still as high as 75.5% after 5000 constant current charge-discharge cycles, indicating that the material has excellent cycle stability. In addition, the coulombic efficiency after cycling is as high as 105.5%, further verifying that the Fe-MoS2 / ReS2 heterostructure nanoelectrically conductive material has good charge storage and release efficiency as an electrode material.

[0080] Therefore, the Fe-MoS2 / ReS2 heterostructure nanoelectrically conductive material selectively doped with iron, its preparation method and application, provide a preparation method which is simple, environmentally friendly and low cost, and does not require subsequent processing. The obtained product has the characteristics of high repeatability, uniform and controllable components, and has broad application prospects in the field of electrochemical energy storage.

[0081] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application but not to limit it, although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that: it can still modify or equivalently replace the technical solutions of the present application, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. A method for preparing iron-selectively doped MoS2 / ReS2 heterostructured conductive nanomaterials, characterized in that: Includes the following steps, S1. After cutting the conductive carbon fiber fabric, immerse it in a mixed solution of concentrated nitric acid and concentrated sulfuric acid. After immersion, ultrasonic treatment is performed, followed by cleaning and drying to obtain the cleaned conductive carbon fiber fabric. S2. Add ferric sulfate, ammonium molybdate tetrahydrate, ammonium perrhenate and thiourea to deionized water in sequence and stir until homogeneous to obtain a mixed solution of reactants; In S2, the amount of ferric sulfate in the reactant mixture is 0.001-0.10 mmol / mL, the amount of ammonium molybdate tetrahydrate is 0.008-0.50 mmol / mL, the amount of thiourea is 0.1-0.50 mmol / mL, and the amount of ammonium perrhenate is 0.025-0.10 mmol / mL. S3. Pour the reactant mixture obtained in S2 into the polytetrafluoroethylene liner of the reactor, then immerse the cleaned conductive carbon fiber fabric obtained in S1 into the reactant mixture, and seal the reactor. S4. Heat the reaction vessel in S3, keep it at the temperature, and then let it cool naturally to room temperature. Take out the sample after the reaction is complete, clean it, vacuum dry it, and then cool it to room temperature to obtain Fe-MoS2 / ReS2 heterostructure nanoconductive material. In S4, the temperature is increased to 180-200℃ at a heating rate of 5-10℃ / min and held for 18-20 hours. The ReS2 structure is significantly distorted with complex bond angles, which is not conducive to the stable substitution of iron atoms in its lattice. The directional doping of iron in the MoS2 phase allows iron atoms to preferentially enter the MoS2 lattice and replace the Mo sites therein. This not only induces the formation of lattice defects in MoS2 and regulates its charge distribution, but also enhances the electronic coupling effect of the MoS2 / ReS2 heterojunction, thereby improving the interfacial charge transfer rate and structural stability.

2. The method for preparing an iron-selectively doped MoS2 / ReS2 heterostructure conductive nanomaterial according to claim 1, characterized in that: In S1, the volume ratio of concentrated nitric acid to concentrated sulfuric acid is 1:2-4, and the soaking time is 24-72 hours.

3. The method for preparing an iron-selectively doped MoS2 / ReS2 heterostructure conductive nanomaterial according to claim 1, characterized in that: In S1, the ultrasonic treatment time is 0.1-1h, the ultrasonic treatment is carried out in deionized water, the cleaning is done by rinsing with deionized water 2-6 times, and the drying temperature is 50-70℃.

4. The method for preparing an iron-selectively doped MoS2 / ReS2 heterostructure conductive nanomaterial according to claim 1, characterized in that: In S2, the stirring speed is 300-500 r / min, and the stirring time is 5-30 min.

5. The method for preparing an iron-selectively doped MoS2 / ReS2 heterostructure conductive nanomaterial according to claim 1, characterized in that: In S3, the reactant mixture solution accounts for 45-80% of the volume of the polytetrafluoroethylene liner, and the cleaned conductive carbon fiber fabric is completely immersed in the reactant mixture solution.

6. The method for preparing an iron-selectively doped MoS2 / ReS2 heterostructure conductive nanomaterial according to claim 1, characterized in that: In S4, the cleaning process involves alternating between deionized water and ethanol 3-5 times, followed by drying at a temperature of 65-75℃ for 6-24 hours.

7. An iron-selectively doped MoS2 / ReS2 heterostructured conductive nanomaterial, characterized in that: The Fe-MoS2 / ReS2 heterostructure conductive nanomaterial was prepared using the method for preparing iron-selectively doped MoS2 / ReS2 heterostructure conductive nanomaterial as described in any one of claims 1-6.

8. An application of an iron-selectively doped MoS2 / ReS2 heterostructure nanoconductive material, characterized in that: The Fe-MoS2 / ReS2 heterostructure nanoconductive material of claim 7 is used as an electrode material in supercapacitors.

Images