CN114613606A - M-MoS2@Ti3C2TxHeterostructure material, and construction method and application thereof - Google Patents

Abstract

The invention discloses an M-MoS₂@Ti₃C₂T_xA heterostructure material and a construction method and application thereof belong to the technical field of electrochemical energy storage, and the construction method of the material comprises the following steps: mixing urea, molybdenum trioxide, thioacetamide and Ti₃C₂T_xAdding the mixture into water, and dissolving the mixture to obtain a reaction solution; transferring the reaction solution into a reaction container for hydrothermal reaction, and naturally cooling to room temperature after the reaction is finished; taking out solid precipitate in the reaction vessel, and sequentiallyAnd washing and drying to obtain solid powder, namely the final product. The M-MoS with excellent electrochemical performance is prepared by adopting a one-step hydrothermal method₂@Ti₃C₂T_xThe material has the performances of high specific capacitance value, high rate capability, high cycle stability and the like. The preparation method provided by the invention has the advantages of easily available raw materials, low cost, simple preparation process and suitability for industrial popularization and application.

Description

M-MoS2@Ti3C2TxHeterostructure material and construction method and application thereof

Technical Field

The invention belongs to the technical field of electrochemical energy storage, and particularly relates to M-MoS₂@Ti₃C₂T_xHeterostructure materials, methods of construction and applications thereof.

Background

Transition Metal Dichalcogenides (TMD) are typically two-dimensional materials with specific energy band structures, semiconducting or superconducting properties, etc. MoS₂As a representative member of TMD, its interlayer is bonded by van der waals force, allowing intercalation of electrolyte ions, making it a hot spot material in the fields of supercapacitors, secondary batteries, electrocatalysis, and the like. MoS₂The properties of (A) are closely related to the crystal structure, and there are mainly two typical crystal structures, respectively 2H semiconductor phase (S-MoS)₂) And 1T Metal phase (M-MoS)₂)。S-MoS₂The band gap of the single layer is about 1.9eV, and the single layer shows semi-insulation, which is not beneficial to the electrode material of the super capacitor for energy storage. M-MoS₂Ratio S-MoS₂Has higher conductivity, exhibits metallic characteristics, and has a layer spacing of about 0.95nm and about S-MoS₂1.5 times (0.6 nm) of the total capacitance is beneficial to obtaining more insertion layer type pseudocapacitance, and further high specific capacitance is shown. However, M-MoS₂The specific capacitance value of (a) decreases very quickly with the increase of the current density, and the rate capability is poor. By M-MoS₂The composite material is compounded with a high-conductivity material to prepare a heterostructure, so that the multiplying power performance of the heterostructure can be improved.

Transition metal carbon/nitride (MXene) as new two-dimensional material with chemical formula of M_n+1X_nT_x(e.g., Ti)₃C₂MXene can also be written as Ti₃C₂T_x) Wherein T is_xSurface functional groups of MXenes (e.g., O, F and OH), Ti₃C₂T_xAs the first reportedThe MXene has ultrahigh electronic conductivity reaching 150000S m^-1The material shows excellent rate performance and cycle stability when used as a supercapacitor electrode.

Thus, by assembling M-MoS₂With Ti₃C₂T_xConstruction of M-MoS₂@Ti₃C₂T_xThe heterostructure is expected to be a material with high capacitance and high rate capability.

Disclosure of Invention

The invention aims to provide an M-MoS₂@Ti₃C₂T_xHeterostructure material, construction method and application thereof, aiming at solving the problem of M-MoS in the prior art₂Unstable performance and poor rate capability.

In order to achieve the purpose, the invention adopts the technical scheme that:

M-MoS₂@Ti₃C₂T_xThe method for constructing the heterostructure material comprises the following steps:

(1) reducing agent, molybdenum trioxide, sulfur source and Ti₃C₂T_xAdding the mixture into water, and dissolving the mixture to obtain a reaction solution; preferably, the reducing agent is urea; the sulfur source is thioacetamide or sodium sulfide; the urea, the molybdenum trioxide, the thioacetamide and the Ti₃C₂T_xThe mass ratio of (A) to (B) is 120: 79: 42: (4-10). The raw material molybdenum trioxide used in the invention is orthorhombic and contains octahedral MoO₆The formed layered structure is beneficial to preparing the metal MoS containing the Mo-S octahedral structure₂(M-MoS₂) Further, M-MoS is constructed₂@Ti₃C₂T_xA heterostructure.

(2) Transferring the reaction liquid to a reaction container for hydrothermal reaction, and naturally cooling to room temperature after the reaction is finished; preferably, the reaction vessel is a high-pressure reaction kettle with a polytetrafluoroethylene lining; the temperature of the hydrothermal reaction is 160-220 ℃, and the time is 10-16 h; specifically, the temperature of the hydrothermal reaction can be 160 ℃, 180 ℃, 200 ℃ or 220 ℃, and the time can be 10h, 12h, 14h or 16 h.

(3) Taking out the solid precipitate in the reaction container, and sequentially washing and drying to obtain solid powder, namely M-MoS₂/Ti₃C₂T_xA heterostructure material. Preferably, the washing method comprises the steps of respectively washing the raw materials for several times by using deionized water and absolute ethyl alcohol; the drying is carried out in a vacuum drying oven, and the drying temperature is 50-70 ℃.

The invention also discloses an electrode and a preparation method of the electrode, and the preparation method of the electrode comprises the following steps:

(1) dispersing a binder, a conductive agent and an active material in an organic solvent to obtain slurry; the active material is M-MoS prepared by the method₂@Ti₃C₂T_xA heterostructure material; preferably, the binder is PVDF, the conductive agent is acetylene black, and the organic solvent is NMP solution. Preferably, the current collector is carbon paper, the coating area of the slurry is controlled to be 1cm multiplied by 1cm, and the coating quality is controlled to be about 1.5 mg.

(2) And coating the slurry on a current collector and drying to obtain the electrode.

The invention also aims to disclose a super capacitor, which comprises the electrode.

The invention has the following beneficial effects:

the M-MoS with excellent electrochemical performance is prepared by adopting a simple one-step hydrothermal method₂@Ti₃C₂T_xA heterostructure material. The M-MoS₂@Ti₃C₂T_xWhen the heterostructure material is used as a cathode material of a super capacitor, the heterostructure material has good characteristics, such as: high specific capacitance value, high rate performance, high cycle stability and the like. The method has the advantages of easily available raw materials, low cost, low reaction temperature, almost no pollution to the environment, no need of adding a surfactant, easy separation of products, high purity of the obtained products, good and uniform appearance, simple preparation process and suitability for industrial popularization and application.

Drawings

FIG. 1 shows M-MoS prepared in example 1₂@Ti₃C₂T_xHeterostructure material and M-MoS prepared in comparative example 1₂X-ray diffraction (XRD) pattern of (a);

FIG. 2 is a graph of M-MoS prepared in comparative example 1₂Scanning electron microscope photographs;

FIG. 3 shows M-MoS prepared in example 1₂@Ti₃C₂T_xHeterostructure material and raw material Ti₃C₂T_xScanning electron microscope photograph of

FIG. 4 shows M-MoS prepared in example 1₂@Ti₃C₂T_xHeterostructure material and M-MoS prepared in comparative example 1₂XPS spectra (S2 p);

FIG. 5 shows M-MoS prepared in example 1₂@Ti₃C₂T_xHeterostructure material and M-MoS prepared in comparative example 1₂XPS spectrum (Mo 3 d);

FIG. 6 shows M-MoS prepared in example 1₂@Ti₃C₂T_xRaman spectra of the heterostructure materials;

FIG. 7 is a cyclic voltammogram of the electrode 1 prepared in application example 1 at different scan rates;

fig. 8 is a constant current charge and discharge curve of the electrode 1 prepared in application example 1 at different current densities;

FIG. 9 is a graph of rate performance of electrode 1 and electrode 2 in a three-electrode test system;

FIG. 10 is a test result of 5000 cycles stability of electrode 1 at a current density of 20A/g in a three-electrode test system.

Detailed Description

The present invention will be further described with reference to the following examples so that those skilled in the art can better understand the present invention and can practice the present invention, but the examples are not intended to limit the present invention; the starting materials used in the following examples and comparative examples are all commercially available products.

Example 1

M-MoS₂@Ti₃C₂T_xThe preparation method of the heterostructure material comprises the following steps:

(1) accurately weighing 1.2g of urea, 0.79g of molybdenum trioxide, 0.42g of thioacetamide and 0.06g of Ti₃C₂T_xThe mixture was dispersed in a beaker containing 60mL of deionized water and was fully dissolved under magnetic stirring to form a homogeneous solution, and a reaction solution was obtained.

(2) And (3) transferring the reaction solution into a high-pressure reaction kettle with a capacity of 100mL and a polytetrafluoroethylene lining, heating in an oven at the constant temperature of 200 ℃ for 12h, and naturally cooling to room temperature after the reaction is finished.

(3) Taking out black precipitate at the bottom of the polytetrafluoroethylene lining, washing with deionized water and absolute ethyl alcohol for 3 times respectively, and drying in a vacuum drying oven at 60 deg.C to constant weight to obtain black solid powder, namely M-MoS₂@Ti₃C₂T_xA heterostructure material.

Application example 1

A method of making an electrode comprising the steps of:

(5) 0.005g of PVDF, 0.005g of acetylene black and 0.04g of M-MoS prepared in example 1 are weighed out₂@Ti₃C₂T_xPutting the heterostructure material into an agate mortar, dropwise adding 0.6ml of NMP solution, and fully grinding for 10min to obtain slurry;

(6) and uniformly coating the slurry on carbon paper, controlling the coating area to be 1cm multiplied by 1cm, putting the uniformly coated carbon paper in a vacuum drying box, and drying at 60 ℃ until the weight is constant to obtain a corresponding electrode, and marking as the electrode 1.

Comparative example 1

Comparative example 1 differs from example 1 in that: in the step (1), Ti is not added₃C₂T_xThe other processes were the same as in example 1. Preparing to obtain M-MoS₂A material.

Referring to the preparation method of the electrode in application example 1, the product M-MoS prepared in comparative example 1 was used₂Material substitution for M-MoS₂@Ti₃C₂T_xHeterostructure material, electrode was prepared as the same and is designated electrode 2.

Structural characterization and performance testing:

for the M-MoS prepared in example 1₂@Ti₃C₂T_xHeterostructure material and M-MoS prepared by comparative example₂The materials were characterized and the results are shown in FIGS. 1-6.

FIG. 1 shows M-MoS prepared in example 1₂@Ti₃C₂T_xHeterostructure material and M-MoS prepared in comparative example 1₂The lower color curve in FIG. 1 is M-MoS₂@Ti₃C₂T_xAn XRD profile of the heterostructure material comprising two characteristic diffraction peaks (002), each at 2 theta-7.0 ° (Ti)₃C₂T_x(002) diffraction peak) and 2 θ of 9.0 ° (M-MoS)₂(002) diffraction peak of (1). And pure M-MoS₂Only one (002) diffraction peak, located at 2 θ, 9.0 °. As can be seen from FIG. 1, M-MoS was successfully prepared by the method of the present invention₂@Ti₃C₂T_xA heterostructure material.

FIG. 2 is a graph of M-MoS prepared in comparative example 1₂Scanning electron micrograph of (1), pure M-MoS can be seen from FIG. 2₂The microtopography of (a) is a nanosheet.

FIG. 3 shows M-MoS prepared in example 1₂@Ti₃C₂T_xHeterostructure material (b) and raw material Ti₃C₂T_x(a) Scanning Electron Microscopy (SEM) photograph of (1). (a) As can be seen, pure Ti₃C₂T_xThe surface is very clean, and the micro-meter sheet is in an accordion shape. (b) It can be seen that₃C₂T_xThe surface is uniformly grown with a substance which is M-MoS according to XRD of figure I₂Thus, M-MoS was successfully prepared₂@Ti₃C₂T_xA heterostructure material.

Comparing FIG. 4 and FIG. 5, M-MoS₂@Ti₃C₂T_xHeterostructure materials and pure M-MoS₂The change (. about.1.1 eV) in the binding energy of S and Mo elements in (1) confirmed that M-MoS₂@Ti₃C₂T_xM-MoS in heterostructure materials₂With Ti₃C₂T_xThere is a chemical bond between them.

M-MoS in FIG. 6₂@Ti₃C₂T_xThe heterostructure material is 147cm^-1、235cm^-1、335cm^-1Three typical Raman peaks J appear₁、J₂、J₃Showing a metal phase MoS₂And is in the range of 280cm^-1Appear E_1gRaman peak, proving Mo in M-MoS₂@Ti₃C₂T_xOctahedral coordination in the heterostructure further demonstrates the metallic phase MoS in the heterostructure₂。

Carrying out electrochemical test on the electrode 1 and the electrode 2 in a three-electrode test system, wherein the relevant conditions are as follows: the working electrode is an electrode 1 or an electrode 2, the reference electrode is an Ag/AgCl electrode, the counter electrode is a platinum sheet electrode, and the electrolyte is 1M sodium sulfate solution. The test results are shown in FIGS. 7-10.

FIG. 7 is a cyclic voltammogram of electrode 1 at different scan rates, which is rectangular-like in shape, and shows that the electrode is a capacitive electrode material with a voltage window of-0.8-0.0V, and is a supercapacitor negative electrode material.

Fig. 8 is a constant current charge and discharge curve of the electrode 1 at different current densities, the linear curve characteristics of which further indicate the capacitive behavior of the heterostructure.

Fig. 9 is a rate performance curve of the electrode 1 and the electrode 2 in the three-electrode test system, and it can be seen from fig. 9 that the specific capacitance values of the electrode 1 and the electrode 2 are almost equal when the current density is 2A/g, but the specific capacitance value of the electrode 2 decreases rapidly with the increase of the current density, and the specific capacitance value is only the initial 39.4% when the current density is increased to 20A/g. The specific capacitance value of the electrode 1 can still keep 75.75% of the initial value, and excellent rate performance is shown. The excellent electrochemical performance of the electrode 1 benefits from M-MoS₂@Ti₃C₂T_xSynergistic effect of each component in the heterostructure material.

FIG. 10 is a graph of the cycling stability of electrode 1 at a current density of 20A/g, fromIt can be known that 5000 times of constant current charge and discharge tests show that the capacity retention rate is as high as 95%, which indicates that the M-MoS₂@Ti₃C₂T_xThe heterostructure material has excellent stability.

Example 2

(1) Accurately weighing 1.2g of urea, 0.79g of molybdenum trioxide, 0.42g of thioacetamide and 0.04g of Ti₃C₂T_xThe mixture was dispersed in a beaker containing 60mL of deionized water and was fully dissolved under magnetic stirring to form a homogeneous solution.

(2) And transferring the uniform solution into a high-pressure reaction kettle with a capacity of 100mL and a polytetrafluoroethylene lining, heating in an oven at the constant temperature of 200 ℃ for 12h, and naturally cooling to room temperature after the reaction is finished.

(3) Taking out black precipitate at the bottom of the polytetrafluoroethylene lining, and washing the black precipitate for 3 times respectively by deionized water and absolute ethyl alcohol to obtain black solid powder.

Example 3

(1) Accurately weighing 1.2g of urea, 0.79g of molybdenum trioxide, 0.42g of thioacetamide and 0.08g of Ti₃C₂T_xThe mixture was dispersed in a beaker containing 60mL of deionized water and was fully dissolved under magnetic stirring to form a homogeneous solution.

(2) And transferring the uniform solution into a high-pressure reaction kettle with a capacity of 100mL and a polytetrafluoroethylene lining, heating in an oven at the constant temperature of 200 ℃ for 12h, and naturally cooling to room temperature after the reaction is finished.

(3) Taking out black precipitate at the bottom of the polytetrafluoroethylene lining, and washing the black precipitate for 3 times respectively by deionized water and absolute ethyl alcohol to obtain black solid powder.

Example 4

(1) Accurately weighing 1.2g of urea, 0.79g of molybdenum trioxide, 0.42g of thioacetamide and 0.1g of Ti₃C₂T_xThe mixture was dispersed in a beaker containing 60mL of deionized water and was fully dissolved under magnetic stirring to form a homogeneous solution.

(2) And transferring the uniform solution into a high-pressure reaction kettle with a capacity of 100mL and a polytetrafluoroethylene lining, heating in an oven at the constant temperature of 200 ℃ for 12h, and naturally cooling to room temperature after the reaction is finished.

(3) Taking out black precipitate at the bottom of the polytetrafluoroethylene lining, and washing the black precipitate for 3 times respectively by deionized water and absolute ethyl alcohol to obtain black solid powder.

Example 5

(1) Accurately weighing 1.2g of urea, 0.79g of molybdenum trioxide, 0.42g of thioacetamide and 0.06g of Ti₃C₂T_xThe mixture was dispersed in a beaker containing 40mL of deionized water and was fully dissolved under magnetic stirring to form a homogeneous solution.

(2) And transferring the uniform solution into a high-pressure reaction kettle with a capacity of 100mL and a polytetrafluoroethylene lining, heating in an oven at the constant temperature of 200 ℃ for 12h, and naturally cooling to room temperature after the reaction is finished.

(3) Taking out black precipitate at the bottom of the polytetrafluoroethylene lining, and washing the black precipitate for 3 times respectively by deionized water and absolute ethyl alcohol to obtain black solid powder.

Example 6

(1) Accurately weighing 1.2g of urea, 0.79g of molybdenum trioxide, 0.42g of thioacetamide and 0.06g of Ti₃C₂T_xThe mixture was dispersed in a beaker containing 50mL of deionized water and was fully dissolved under magnetic stirring to form a homogeneous solution.

(2) And transferring the uniform solution into a high-pressure reaction kettle with a capacity of 100mL and a polytetrafluoroethylene lining, heating in an oven at the constant temperature of 200 ℃ for 12h, and naturally cooling to room temperature after the reaction is finished.

(3) Taking out black precipitate at the bottom of the polytetrafluoroethylene lining, and washing the black precipitate for 3 times respectively by deionized water and absolute ethyl alcohol to obtain black solid powder.

Example 7

(1) 1.2g of urea, 0.79g of molybdenum trioxide, 0.42g of thioacetamide and 0.06g of Ti are accurately weighed₃C₂T_xThe mixture was dispersed in a beaker containing 70mL of deionized water and was fully dissolved under magnetic stirring to form a homogeneous solution.

(2) And transferring the uniform solution into a high-pressure reaction kettle with a capacity of 100mL and a polytetrafluoroethylene lining, heating in an oven at the constant temperature of 200 ℃ for 12h, and naturally cooling to room temperature after the reaction is finished.

(3) Taking out black precipitate at the bottom of the polytetrafluoroethylene lining, and washing the black precipitate for 3 times respectively by deionized water and absolute ethyl alcohol to obtain black solid powder.

Example 8

(1) Accurately weighing 1.2g of urea, 0.79g of molybdenum trioxide, 0.42g of thioacetamide and 0.06g of Ti₃C₂T_xThe mixture was dispersed in a beaker containing 60mL of deionized water and was fully dissolved under magnetic stirring to form a homogeneous solution.

(2) And transferring the uniform solution into a high-pressure reaction kettle with a capacity of 100mL and a polytetrafluoroethylene lining, heating in a drying oven at the constant temperature of 160 ℃ for 12 hours, and naturally cooling to room temperature after the reaction is finished.

(3) Taking out black precipitate at the bottom of the polytetrafluoroethylene lining, and washing the black precipitate for 3 times respectively by deionized water and absolute ethyl alcohol to obtain black solid powder.

Example 9

(1) Accurately weighing 1.2g of urea, 0.79g of molybdenum trioxide, 0.42g of thioacetamide and 0.06g of Ti₃C₂T_xThe mixture was dispersed in a beaker containing 60mL of deionized water and was fully dissolved under magnetic stirring to form a homogeneous solution.

(2) And transferring the uniform solution into a high-pressure reaction kettle with a capacity of 100mL and a polytetrafluoroethylene lining, heating in an oven at 180 ℃ for 12h at constant temperature, and naturally cooling to room temperature after the reaction is finished.

(3) Taking out black precipitate at the bottom of the polytetrafluoroethylene lining, and washing the black precipitate for 3 times respectively by deionized water and absolute ethyl alcohol to obtain black solid powder.

Example 10

(1) 1.2g of urea, 0.79g of molybdenum trioxide, 0.42g of thioacetamide and 0.06g of Ti are accurately weighed₃C₂T_xDispersing the mixture in a beaker filled with 60mL of deionized water, and fully dissolving the mixture under the action of magnetic stirringTo form a homogeneous solution.

(2) And transferring the uniform solution into a high-pressure reaction kettle with a capacity of 100mL and a polytetrafluoroethylene lining, heating in an oven at 220 ℃ for 12h at constant temperature, and naturally cooling to room temperature after the reaction is finished.

(3) Taking out black precipitate at the bottom of the polytetrafluoroethylene lining, and washing the black precipitate for 3 times respectively by deionized water and absolute ethyl alcohol to obtain black solid powder.

By verifying the products prepared in the above examples and comparative examples, in the preparation process, when the amount of water is changed, the volume of the air column in the reaction kettle is changed, which affects the pressure in the reaction kettle in the hydrothermal reaction and further affects the structure of the final product; in addition, when Ti is changed₃C₂T_xWhen the amount of the Ti is used, the electrochemical performance of the final product is influenced, and the proper Ti is obtained through experiments₃C₂T_xThe prepared product has good specific capacitance value and excellent rate performance.

It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Claims (9)

1. M-MoS₂@Ti₃C₂T_xThe method for constructing the heterostructure material is characterized by comprising the following steps: the method comprises the following steps:

(1) reducing agent, molybdenum trioxide, sulfur source and Ti₃C₂T_xAdding the mixture into water, and dissolving the mixture to obtain a reaction solution;

(2) transferring the reaction liquid to a reaction container for hydrothermal reaction, and naturally cooling to room temperature after the reaction is finished;

(3) taking out the solid precipitate in the reaction container, and sequentially washing and drying to obtain solid powder, namely M-MoS₂@Ti₃C₂T_xA heterostructure material.

2. The M-MoS of claim 1₂@Ti₃C₂T_xThe method for constructing the heterostructure material is characterized by comprising the following steps: in the step (1), the reducing agent is urea; the sulfur source is thioacetamide or sodium sulfide.

3. The M-MoS of claim 1₂@Ti₃C₂T_xThe method for constructing the heterostructure material is characterized by comprising the following steps: in the step (2), the reaction vessel is a high-pressure reaction kettle with a polytetrafluoroethylene lining.

4. The M-MoS of claim 1₂@Ti₃C₂T_xThe method for constructing the heterostructure material is characterized by comprising the following steps: in the step (2), the temperature of the hydrothermal reaction is 160-220 ℃, and the time is 10-16 h.

5. The M-MoS of claim 1₂@Ti₃C₂T_xThe method for constructing the heterostructure material is characterized by comprising the following steps: in the step (3), the washing method comprises the steps of respectively washing the raw materials for a plurality of times by using deionized water and absolute ethyl alcohol; the drying is carried out in a vacuum drying oven, and the drying temperature is 50-70 ℃.

6. M-MoS₂@Ti₃C₂T_xHeterostructure material, characterized in that: the M-MoS₂@Ti₃C₂T_xThe heterostructure material is prepared by the construction method as claimed in any one of claims 1 to 5.

7. A method for preparing an electrode, comprising: the method comprises the following steps:

(1) dispersing a binder, a conductive agent and an active material in an organic solvent to obtain slurry; the active material is the M-MoS of claim 6₂@Ti₃C₂T_xHeterogeneous structure materialFeeding;

(2) and coating the slurry on a current collector and drying to obtain the electrode.

8. An electrode, characterized by: the electrode is produced by the production method according to claim 7.

9. A supercapacitor, characterized by: the supercapacitor comprising the electrode of claim 8.

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