CN113611831B

CN113611831B - MXene/SnSe0.5S0.5Composite material and preparation method and application thereof

Info

Publication number: CN113611831B
Application number: CN202110854451.1A
Authority: CN
Inventors: 程娅伊; 孟志新; 曹静; 史冰垚; 李东升; 王雪
Original assignee: Xian Aeronautical University
Current assignee: Xian Aeronautical University
Priority date: 2021-07-28
Filing date: 2021-07-28
Publication date: 2022-07-12
Anticipated expiration: 2041-07-28
Also published as: CN113611831A

Abstract

The invention discloses MXene/SnSe_0.5S_0.5The composite material and the preparation method and the application thereof are characterized in that MAX is etched by HF; adding the obtained etching product into a layer expanding agent to obtain a layer expanding product; adding the layer expanding product into ethylene glycol to obtain a mixture A; adding selenium powder and sulfur powder into a reducing solvent to obtain a mixture B; dripping the mixture B into the mixture A, and performing microwave solvothermal reaction and solvothermal reaction to obtain MXene/SnSe_0.5S_0.5A composite material. The invention MXene/SnSe_0.5S_0.5The composite material and the preparation method and application thereof take MXene with obvious layered structure as a matrix, and the high-purity MXene/SnSe is prepared by adopting a microwave-assisted solvothermal method and combining with the traditional solvothermal method_0.5S_0.5The compound is used as a negative electrode material of a sodium ion button cell, and shows high reversible capacity and cycling stability.

Description

MXene/SnSe0.5S0.5Composite material and preparation method and application thereof

Technical Field

The invention belongs to the technical field of ternary alloys for a sodium ion battery cathode, and relates to MXene/SnSe_0.5S_0.5A composite material and a preparation method and application thereof.

Background

The problems of large energy consumption and environmental destruction cause that human beings urgently need renewable new energy sources to replace non-renewable fossil energy sources. However, the renewable new energy is greatly influenced by the environment and climate in the actual use process, and cannot provide continuous and stable energy supply, and the supply efficiency and stability of energy can be improved by designing an excellent electrochemical energy storage device.

Lithium ion batteries, which are one type of electrochemical devices, are widely used because of their many advantages, such as high energy density, long cycle life, and small size. However, the reserve of lithium resources in the earth crust is limited, which seriously hinders its continued development. Therefore, researchers are focusing on sodium ion batteries, and most of the positive and negative electrode materials for lithium ion batteries are also suitable for sodium ion batteries because sodium resources are very abundant in earth shells and have electrochemical energy storage mechanisms similar to those of the lithium ion batteries.

The electrode material is the most important factor for restricting the performance of the battery, the positive electrode is relatively mature, and for the negative electrode, the commercialized graphite negative electrode cannot meet the requirements of the battery on high capacity, high energy density and the like, so that the search for a new negative electrode material to replace graphite is urgently needed.

Among the cathode materials, the tin-based cathode material has received much attention from researchers due to its high theoretical specific capacity, and includes unitary elemental tin, binary tin-based oxides and sulfides, and ternary tin-based chalcogenides. Wherein, the monobasic and binary tin-based cathode materials are easy to agglomerate in the process of sodium storage, so that the sodium storage activity of the cathode materials is gradually reduced in the circulating process. In contrast, ternary tin-based chalcogenides SnSe_0.5S_0.5Sn and Na can be formed in the sodium storage reaction₂S、Na₂Se and other intermediate phases, and the heterogeneous species can form a multi-phase interface to inhibit the sodium storage intermediate phases from migrating and coarsening with each other, so that high sodium storage activity is obtained, and simultaneously, SnSe and other intermediate phases can form a multi-phase interface to inhibit the sodium storage intermediate phases from migrating and coarsening_0.5S_0.5The lithium ion battery has a layered crystal structure, and a weak van der Waals force system is used between layers, so that a rapid channel can be provided for the deintercalation of sodium ions, and the lithium ion battery has the potential of becoming an excellent cathode material. However, SnSe_0.5S_0.5Similar to other tin-based anode materials, their ionic and electronic conductivities are low and there is a large volume expansion during cycling, resulting in SnSe_0.5S_0.5Is poor in electrochemical performance, therefore, SnSe_0.5S_0.5Relatively few reports have been made as electrode materials.

At present, SnSe_0.5S_0.5Mainly focuses on CVT (chemical vapor transport) and CVD (chemical vapor deposition), but the method has difficulty in obtaining nano-scale SnSe_0.5S_0.5The material has limited electrochemical performance as the cathode material of the sodium-ion battery. Concerning SnS_0.5Se_0.5The application of electrode materials is rarely reported, and the main reason is that nano-scale SnSe is difficult to obtain_0.5S_0.5Materials, research on nano-sized SnSe is urgently needed_0.5S_0.5A preparation process of the material. Even if nano-scale SnSe is obtained_0.5S_0.5The preparation process of the material needs to be deeply explored to obtain a cathode material with high electrochemical performance, high reversible capacity and high cycling stability.

Therefore, there is a strong need to expand SnSe_0.5S_0.5While improving the preparation process to obtain SnSe with excellent electrochemical performance_0.5S_0.5And (3) a negative electrode material.

Disclosure of Invention

In order to achieve the above object, the present invention provides MXene/SnSe_0.5S_0.5The composite material and the preparation method and the application thereof are characterized in that MXene with obvious layered structure is obtained and then used as a matrix to prepare MXene/SnSe with higher purity by combining a microwave-assisted solvothermal method and a traditional solvothermal method_0.5S_0.5A complex of SnSe_0.5S_0.5Uniform size and high degree of crystallization, SnSe_0.5S_0.5The nano particles are adsorbed on the surface of the MXene lamellar structure to form MXene/SnSe_0.5S_0.5As a negative electrode material of a sodium ion button cell, the material shows higher reversible capacity and cycling stability, and solves the problem of nano-scale SnSe existing in the prior art_0.5S_0.5The preparation process of the material is rare, and the electrochemical performance of the material as a negative electrode material is poor.

The technical scheme adopted by the invention is that MXene/SnSe_0.5S_0.5The preparation method of the composite material comprises the following steps:

step 1: adding MAX in a proportion of 1.0 g-3.0 g: adding 25-75 ml of HF aqueous solution with the mass percent of 35-45%, stirring for 6-18 h at the speed of 300-900 r/min at 50-80 ℃ under the condition of water bath, centrifuging, washing and freeze-drying the obtained etching solution to obtain an etching product;

step 2: organic matter containing amino groups is mixed according to the mass volume ratio of 20 mg-100 mg: adding 50 ml-100 ml of the mixture into a dilute hydrochloric acid solution with the concentration of 0.2 mol/L-1.0 mol/L, and stirring at the stirring speed of 300 r/min-900 r/min for 10 min-30 min to obtain a layer expanding agent; the volume ratio of the HF aqueous solution in the step 1 to the dilute hydrochloric acid solution in the step 2 is 1-3: 2-4; adding the etching product obtained in the step (1) into the layer expanding agent, carrying out ultrasonic treatment for 18-72 h at the temperature of 30-50 ℃, and centrifuging, washing and freeze-drying the obtained product to obtain a layer expanding product;

step 31: and (3) coating the layer expanding product obtained in the step (2) in a mass-volume ratio of 50 mg-100 mg: 20ml to 50ml of the mixture is added into glycol, ultrasonic dispersion is carried out for 1h to 3h, and then SnCl is added₂·2H₂O, stirring for 30-90 min to obtain a mixture A;

step 32: adding selenium powder and sulfur powder into a reducing solvent according to the molar ratio of 1:1, and stirring until the selenium powder and the sulfur powder are completely dissolved to obtain a mixture B;

step 33: dropwise adding the mixture B into the mixture A, uniformly stirring, transferring to a microwave reaction kettle, and carrying out microwave solvothermal reaction in a microwave hydrothermal synthesizer to obtain a microwave solvothermal product;

step 34: transferring the microwave solvent thermal product into a stainless steel high-pressure autoclave, carrying out solvent thermal reaction for 3-12 h in an oven at the temperature of 160-200 ℃, centrifuging, washing and freeze-drying the obtained product to obtain MXene/SnSe_0.5S_0.5A composite material.

Further, in step 1, MAX is Ti₃AlC₂The MAX is added at a rate of 0.1g/min to 0.3 g/min.

Further, in step 2, the amino group-containing organic substance includes any one of hydrazine hydrate, ethylenediamine, and dopamine hydrochloride.

Further, in step 31, SnCl₂·2H₂The molar volume ratio of O to glycol is 0.002 mol-0.01 mol: 20ml to 50 ml.

Further, in step 32, selenium powder, sulfur powder and SnCl in step 31₂·2H₂The molar ratio of O is 1:1: 2.

Further, in step 32, the reducing solvent is hydrazine hydrate.

Further, in the step 32, the molar volume ratio of the selenium powder to the reducing solvent is 0.001mol to 0.005 mol: 3ml to 8 ml.

Further, in step 33, the specific process parameters of the microwave solvothermal reaction are as follows: the heating power is 300w, the temperature is between 160 and 220 ℃, and the temperature is kept for 10 to 60min at the temperature.

Another object of the present invention is to provide MXene/SnSe_0.5S_0.5A composite material prepared according to the above preparation method.

Another object of the present invention is to provide the MXene/SnSe mentioned above_0.5S_0.5The composite material is applied to the field of preparing battery cathode materials.

The invention has the beneficial effects that:

(1) the application takes the novel two-dimensional MXene material as a matrix to obtain MXene/SnSe_0.5S_0.5The composite material improves the SnSe by utilizing the advantages of unique layered structure, high ionic conductivity and electronic conductivity, good chemical stability and the like of MXene_0.5S_0.5The ionic conductivity, the electronic conductivity and other electrochemical properties can effectively relieve the SnSe_0.5S_0.5The volume during sodium storage expands.

(2) The method comprises the steps of firstly adopting HF to etch MXene, and then using-NH-containing gas₂The mixed solution of the organic molecules and the dilute HCl is used for carrying out layer expansion on the etched MXene to ensure that the MXene with an obvious layered structure is obtained, and then the MXene/SnSe with higher purity is prepared by taking the MXene as a matrix and adopting a microwave-assisted solvothermal method in combination with the traditional solvothermal method_0.5S_0.5A complex of SnSe_0.5S_0.5Uniform size and high degree of crystallization, SnSe_0.5S_0.5The nano particles are adsorbed on the surface of the MXene lamellar structure to form MXene/SnSe_0.5S_0.5The material is used as a negative electrode material of a sodium ion button cell, and shows higher reversible capacity and cycling stability.

(3) The application adopts the microwave-assisted solvothermal method to combine the traditional solvothermal method for the first time to obtain the high-purity MXene/SnSe_0.5S_0.5The composite not only expands the negative electrode material system of the sodium-ion batteryAnd is SnS_0.5Se_0.5The preparation of the material provides a new method.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a scanning electron micrograph of an etching product in example 1 of the present application.

FIG. 2 shows MXene/SnSe prepared in example 1 of the present application_0.5S_0.5X-ray diffraction pattern of the composite.

FIG. 3 shows MXene/SnSe prepared in example 1 of the present application_0.5S_0.5Scanning electron micrographs of the composite.

FIG. 4 shows MXene/SnSe prepared in example 1 of the present application_0.5S_0.5Cycle performance curve of the composite.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.

The working concept of the invention is as follows: the method comprises the steps of firstly carrying out etching and layer expanding treatment on MAX, then using MXene with a good layered structure as a substrate, and preparing high-purity MXene/SnSe by combining a microwave-assisted solvothermal method and traditional solvothermal_0.5S_0.5Complexes, complexes in which SnSe is present_0.5S_0.5The crystallinity is higher, and the nano particles are shown to be adsorbed on the surface of the MXene matrix. The composite has higher reversible capacity and cycle when being used as a negative electrode material of a sodium-ion batteryRing stability. Because the preparation method is novel, the invention is SnS_0.5Se_0.5The preparation of the nano material provides a new method. Therefore, the method has significant scientific significance in the application of the electrode material of the sodium-ion battery.

MXene/SnSe_0.5S_0.5The preparation method of the composite material comprises the following steps:

step 1: adding MAX into 35-45% HF aqueous solution at the adding rate of 0.1-0.3 g/min, stirring for 6-18 h at 50-80 ℃ under the condition of water bath to obtain etching solution, centrifuging and washing the etching solution until the pH value of the etching solution is close to neutral, collecting centrifugal precipitate, and freeze-drying to obtain an etching product.

The technological parameters of the freeze drying in the step are as follows: putting the obtained product into a culture dish, adding a small amount of deionized water, stirring until the product is completely dispersed uniformly, putting the product into a freeze dryer (TF-LFD-1), freezing for 6-12 h at-20 to-40 ℃, and then vacuumizing and drying for 4-10 h at 30-50 ℃ to obtain a dry powdery etching product.

Ti is preferably used in this step MAX₃AlC₂(ii) a The mass-to-volume ratio of MAX to HF aqueous solution is: 1.0 g-3.0 g: 25 ml-75 ml, under the condition of said proportion a proper quantity of HF aqueous solution can make MAX and HF fully contact so as to attain the goal of etching, and can not waste HF aqueous solution; the mass fraction of the HF aqueous solution is 35-45%, the concentration of HF acid is too low below 35%, the aim of etching MAX cannot be achieved, and the concentration of HF aqueous solution is too high above 45%, the layered structure of an etching product is damaged; the stirring speed of the stirring is 300 r/min-900 r/min.

This step Ti₃AlC₂Etching with HF aqueous solution to etch Al atomic layer, and etching Ti₃C₂The layered crystal structure of the material is not damaged, so that a layered material is obtained, and the etching product obtained in the step is analyzed by XRD (X-ray diffraction) characterization, as shown in figure 2, more Ti appears in the diffraction peak₃C₂Diffraction peaks, indicating that the Al atomic layer was successfully etched away.

Step 2: firstly, amino group (-NH)₂) By mass ofThe volume ratio is 20 mg-100 mg: adding 50 ml-100 ml of diluted hydrochloric acid solution with the concentration of 0.2 mol/L-1.0 mol/L, stirring at the stirring speed of 300 r/min-900 r/min for 10 min-30 min, and uniformly mixing to obtain a layer expanding agent; the volume ratio of the 35-45 mass percent HF aqueous solution in the step 1 to the 0.2-1.0 mol/L dilute hydrochloric acid solution in the step 2 is 1-3: 2-4; adding the etching product obtained in the step 1 into a layer expanding agent, performing ultrasonic treatment for 18-72 h in an ultrasonic cleaning instrument at the temperature of 30-50 ℃ in order to fully contact the etching product with the layer expanding agent and realize a better layer expanding effect, centrifuging and washing the obtained product for 4-6 times, and performing freeze drying to obtain the layer expanding product.

The technological parameters of the freeze drying in the step are as follows: putting the obtained product into a culture dish, adding a small amount of deionized water, stirring until the product is completely dispersed uniformly, putting the product into a freeze dryer (TF-LFD-1), freezing for 6-12 h at-20 to-40 ℃, and then vacuumizing and drying for 4-10 h at 30-50 ℃ to obtain a dry powdery layer expansion product.

The organic matter containing amino group includes any one of hydrazine hydrate, ethylenediamine and dopamine hydrochloride;

this step contains-NH₂The organic substance is added into dilute hydrochloric acid to generate Lewis acid-base reaction to generate Cl salt, and positive charge-NH is generated after hydrolysis₃ ⁺Ions, and the surface of the etching product contains negatively charged groups such as-F, -OH and the like, which makes the surface have-NH₃ ⁺The ionic layer expanding agent is easy to enter the interlayer of an etching product, has obvious layered structure and contains-NH₂The organic matter has large volume, which is beneficial to improving the interlayer spacing of the etching product, thereby achieving the purpose of layer expanding.

The prior art directly adopts the catalyst containing-NH₂The organic matter is used as a layer expanding agent, the organic matter has larger volume and is easy to enter into an etching product layer in the ultrasonic or stirring process, so that the layer expansion is realized, and the layer expansion process depends on physical action. However, as the layer expanding process proceeds, the negative charge groups of-F, -OH and the like on the surface of the etching product and the negative charge groups containing-NH₂The reaction power of the organic matter of (A) gradually decreases, and the etching product isThe layers are easy to be stacked again, so that the layer expanding efficiency is gradually reduced, and the layer expanding is incomplete. In the method, a mixed solution of an organic matter containing amino groups and hydrochloric acid is prepared to serve as a layer expanding agent, and the layer expanding agent with positive charges enters an Mxene layer with negative charges on the surface by virtue of electrostatic attraction of the positive charges and the negative charges.

The layer expanding product obtained in the step has an obvious layered structure, each layer consists of stripped flaky structures, the specific surface area is large, gaps among the layers are large, and the subsequent SnS is facilitated_0.5Se_0.5The loading of the nanoparticles, and the layer-expanding product as the matrix can relieve SnSe_0.5S_0.5Stress generated by sodium ion deintercalation in the process of sodium storage, thereby achieving the purpose of relieving SnSe_0.5S_0.5The purpose of volume expansion.

Step 31: and (3) coating the layer expanding product obtained in the step (2) in a mass-volume ratio of 50 mg-100 mg: adding 20 ml-50 ml of the mixture into ethylene glycol, ultrasonically dispersing for 1 h-3 h, and then adding SnCl₂·2H₂Continuously stirring for 30-90 min to obtain a mixture A;

wherein, SnCl₂·2H₂The molar volume ratio of O to glycol is 0.002 mol-0.01 mol: 20ml to 50 ml.

wherein, SnCl₂·2H₂The molar ratio of O to selenium powder to sulfur powder is 2:1: 1; the reducing solvent is hydrazine hydrate; the molar volume ratio of the selenium powder to the reducing solvent is 0.001-0.005 mol: 3ml to 8 ml.

the microwave reaction kettle adopts a polytetrafluoroethylene lining, and the product model of the microwave hydrothermal synthesizer adopts MDS-8;

the specific technological parameters of the microwave solvothermal reaction are as follows: heating power is 300w, heating to 160-220 ℃, and preserving heat for 10-60 min at the temperature;

the step adopts microwave solvothermal reaction to obtain a uniform thermal physical field, and ethylene glycol as a solvent has higher microwave absorption rate, so that the reaction time can be obviously shortened, and SnSe can be obtained_0.5S_0.5Uniform nucleation in a short time without growth, and small-sized and uniform SnSe_0.5S_0.5Nanocrystals, SnSe of the structure_0.5S_0.5Has more and evenly distributed sodium storage active sites, less stress generated by the deintercalation of sodium ions in the sodium storage active sites, and evenly distributed SnSe_0.5S_0.5The nanocrystalline has a certain stress relieving effect, and the structure can not be damaged due to stress concentration, so that the reversible capacity of the nanocrystalline can be well maintained, and the stability is high.

Step 34: transferring the microwave solvent thermal product into a stainless steel high-pressure kettle, carrying out solvent thermal reaction in an oven, centrifuging, washing and freeze-drying the obtained product to obtain MXene/SnSe_0.5S_0.5A composite material;

the technological parameters of the freeze drying in the step are as follows: putting the obtained product into a culture dish, adding a small amount of deionized water, stirring until the product is completely dispersed uniformly, putting the product into a freeze dryer (TF-LFD-1), freezing the product for 6 to 12 hours at the temperature of between 20 ℃ below zero and 40 ℃ below zero, vacuumizing the product, and drying the product for 4 to 10 hours at the temperature of between 30 and 50 ℃ to obtain dry powdery MXene/SnSe_0.5S_0.5A composite material.

The stainless steel autoclave adopts a polytetrafluoroethylene lining;

the specific process conditions of the solvothermal reaction are as follows: reacting for 3-12 h at 160-200 ℃; under the process condition, the SnSe can be improved_0.5S_0.5Without growing its nuclei, to maintain a small nanocrystal size. SnSe with good crystallinity_0.5S_0.5Has better structural stability in the process of storing sodium and can obtain stable cycle performance.

This step is based on the uniform small-sized microwave solvothermal product obtained in step 33By conventional solvothermal method, increase of SnSe_0.5S_0.5The crystallinity of (2). According to the preparation scheme of firstly performing microwave solvothermal reaction and then performing conventional solvothermal reaction, the SnSe which is uniformly distributed on the layer-expanding product and has good crystallinity, small size and uniformity is obtained_0.5S_0.5The nano-crystals are uniformly distributed on the surface of the MXene layered structure, and compared with the existing report, the nano-crystals have a more obvious sodium storage advantage.

If only the conventional solvothermal method in step 34 is adopted and the microwave solvothermal method in step 33 is not adopted, the SnSe in the whole reaction system is caused by uneven distribution of heat sources_0.5S_0.5Lead to MXene surface SnSe_0.5S_0.5The size of the nano crystal is not uniform, even SnSe appears in partial area_0.5S_0.5Phenomenon of agglomeration, SnSe_0.5S_0.5The agglomeration of (A) can lead to uneven stress distribution and local concentration generated in the process of sodium ion deintercalation, thus leading to MXene/SnSe_0.5S_0.5The local structure of the compound is destroyed, and the release of SnSe can not be realized_0.5S_0.5Effect of volume expansion with SnSe_0.5S_0.5The size of the nano-crystal is uneven, the regularity is poor, the uniformity is poor, and the de-intercalation of lithium and sodium ions is not facilitated.

Example 1

(1) 3.0g of Ti₃AlC₂Adding the mixture into 75ml of HF aqueous solution with the mass percent of 45% at the speed of 0.3g/min, stirring for 18 hours at the speed of 900r/min at the temperature of 80 ℃ under the condition of water bath, centrifuging and washing the obtained etching solution, placing the obtained product into a culture dish, adding a small amount of deionized water, stirring until the product is completely and uniformly dispersed, placing the product into a freeze dryer, freezing for 9 hours at the temperature of-30 ℃, and then vacuumizing and drying for 7 hours at the temperature of 40 ℃ to obtain a dry powdery etching product.

(2) Adding 100mg of dopamine hydrochloride into 100ml of 1.0mol/L diluted hydrochloric acid solution, and stirring at the stirring speed of 900r/min for 30min to obtain a spreading agent; adding the etching product obtained in the step (1) into the layer expanding agent, carrying out ultrasonic treatment for 72 hours at the temperature of 50 ℃, centrifuging, washing and freeze-drying the obtained product (the process parameters are the same as those in the step (1)) to obtain a layer expanding product; as shown in FIG. 1, the layer-extended product obtained in this step was observed by a field emission scanning electron microscope (FES) model No. S4800, which had a distinct layered structure;

(3) adding 100mg of the layer expanding product obtained in the step (2) into 50ml of ethylene glycol, carrying out ultrasonic dispersion for 3 hours, and then adding 0.01mol of SnCl₂·2H₂O, stirring for 90min to obtain a mixture A;

(4) adding 0.005mol of selenium powder and 0.005mol of sulfur powder into 8ml of hydrazine hydrate, and stirring until the selenium powder and the sulfur powder are completely dissolved to obtain a mixture B;

(5) dropwise adding the mixture B into the mixture A, uniformly stirring, transferring to a microwave reaction kettle, and carrying out microwave solvothermal reaction in a microwave hydrothermal synthesizer, wherein the method specifically comprises the following steps: heating to 220 ℃ with the heating power of 300w, and preserving the heat for 60min at the temperature to obtain a microwave solvent thermal product;

(6) transferring the microwave solvent thermal product into a stainless steel autoclave, carrying out solvent thermal reaction for 12h in an oven at the temperature of 200 ℃, centrifuging, washing and freeze-drying the obtained product (the process parameters are the same as those in the step (1)) to obtain MXene/SnSe_0.5S_0.5A composite material.

As shown in FIG. 2, MXene/SnSe obtained in this example were analyzed by a Japanese XRD Rigaku Ultima IV X-ray diffractometer_0.5S_0.5Composite powder, sample and SnS with JCPDS serial number of 48-1225_0.5Se_0.5The structures are consistent, and the remaining peaks correspond to the peaks of MXene. As shown in FIG. 3, MXene/SnSe obtained in this example was observed with a field emission Scanning Electron Microscope (SEM) model S4800_0.5S_0.5Composite material, SnSe_0.5S_0.5The nano particles are uniformly adsorbed on the surface of the MXene matrix.

Example 2

(1) 1.0g of Ti₃AlC₂Adding the mixture into 25ml of 35 mass percent HF aqueous solution at the speed of 0.1g/min, stirring for 6 hours at the speed of 300r/min at the temperature of 50 ℃ under the condition of water bath, centrifuging and washing the obtained etching solution, placing the obtained product into a culture dish, adding a small amount of deionized water, stirring until the product is completely and uniformly dispersed, placing the product into a freeze dryer, freezing for 6 hours at the temperature of minus 20 ℃, vacuumizing and drying for 10 hours at the temperature of 30 ℃ to obtain a dry powdery etching product;

(2) adding 20mg of hydrazine hydrate into 50ml of dilute hydrochloric acid solution with the concentration of 0.2mol/L, and stirring for 10min at the stirring speed of 300r/min to obtain a layer expanding agent; adding the etching product obtained in the step (1) into a layer expanding agent, carrying out ultrasonic treatment for 18h at the temperature of 30 ℃, centrifuging and washing the obtained product for 4 times respectively, and carrying out freeze drying (the process parameters are the same as those in the step (1)) to obtain a layer expanding product;

(3) adding 50mg of the layer expanding product obtained in the step (2) into 20ml of ethylene glycol, performing ultrasonic dispersion for 1h, and then adding 0.002mol of SnCl₂·2H₂O, stirring for 30min to obtain a mixture A;

(4) adding 0.001mol of selenium powder and 0.001mol of sulfur powder into 3ml of hydrazine hydrate, and stirring until the selenium powder and the sulfur powder are completely dissolved to obtain a mixture B;

(5) dropwise adding the mixture B into the mixture A, uniformly stirring, transferring to a microwave reaction kettle, and carrying out microwave solvothermal reaction in a microwave hydrothermal synthesizer, wherein the method specifically comprises the following steps: heating to 160 ℃ under the condition that the heating power is 300w, and preserving the heat for 10min at the temperature to obtain a microwave solvent thermal product;

(6) transferring the microwave solvent thermal product into a stainless steel autoclave, carrying out solvent thermal reaction for 3h in an oven at the temperature of 160 ℃, centrifuging and washing the obtained product for 5 times respectively, and freeze-drying (the process parameters are the same as those in the step (1)) to obtain MXene/SnSe_0.5S_0.5A composite material.

Example 3

(1) 2.0g of Ti₃AlC₂Adding into 50ml of solution at a rate of 0.2g/minStirring in 40% HF aqueous solution at a speed of 600r/min for 12h at 65 ℃ under a water bath condition, centrifuging and washing the obtained etching solution, putting the obtained product into a culture dish, adding a small amount of deionized water, stirring until the product is completely dispersed uniformly, putting the product into a freeze dryer, freezing for 12h at-40 ℃, vacuumizing and drying for 4h at 50 ℃ to obtain a dry powdery etching product;

(2) adding 60mg of ethylenediamine into 75ml of 0.6mol/L dilute hydrochloric acid solution, and stirring at a stirring speed of 600r/min for 20min to obtain a layer expanding agent; adding the etching product obtained in the step (1) into the layer expanding agent, performing ultrasonic treatment for 45 hours at the temperature of 40 ℃, centrifuging, washing and freeze-drying the obtained product (the process parameters are the same as those in the step (1)) to obtain a layer expanding product;

(3) adding 75mg of the layer expanding product obtained in the step (2) into 35ml of ethylene glycol, performing ultrasonic dispersion for 2 hours, and then adding 0.006mol of SnCl₂·2H₂O, stirring for 60min to obtain a mixture A;

(4) adding 0.003mol of selenium powder and 0.003mol of sulfur powder into 5.5ml of hydrazine hydrate, and stirring until the selenium powder and the sulfur powder are completely dissolved to obtain a mixture B;

(5) dropwise adding the mixture B into the mixture A, uniformly stirring, transferring to a microwave reaction kettle, and carrying out microwave solvothermal reaction in a microwave hydrothermal synthesizer, wherein the method specifically comprises the following steps: heating to 190 ℃ with the heating power of 300w, and keeping the temperature for 35min at the temperature to obtain a microwave solvothermal product;

(6) transferring the microwave solvent thermal product into a stainless steel autoclave, carrying out solvent thermal reaction for 7.5h in an oven at the temperature of 190 ℃, centrifuging, washing and freeze-drying the obtained product (the process parameters are the same as those in the step (1)) to obtain MXene/SnSe_0.5S_0.5A composite material.

Example 4

(1) 1.5g of Ti₃AlC₂Adding into 37.5ml of 38% HF aqueous solution at a rate of 0.15g/min, and heating at 57 deg.C in a water bathStirring at the speed of 450r/min for 7.5h, centrifuging and washing the obtained etching solution, putting the obtained product into a culture dish, adding a small amount of deionized water, stirring until the product is completely and uniformly dispersed, putting the product into a freeze dryer, freezing the product at the temperature of minus 25 ℃ for 8h, vacuumizing the product, and drying the product at the temperature of 35 ℃ for 8h to obtain a dry powdery etching product;

(2) adding 40mg of hydrazine hydrate into 62ml of dilute hydrochloric acid solution with the concentration of 0.4mol/L, and stirring for 15min at the stirring speed of 450r/min to obtain a layer expanding agent; adding the etching product obtained in the step (1) into the layer expanding agent, carrying out ultrasonic treatment for 32 hours at the temperature of 35 ℃, centrifuging, washing and freeze-drying the obtained product (the process parameters are the same as those in the step (1)) to obtain a layer expanding product;

(3) adding 62mg of the layer expanding product obtained in the step (2) into 27ml of ethylene glycol, carrying out ultrasonic dispersion for 1.5h, and then adding 0.004mol of SnCl₂·2H₂O, stirring for 45min to obtain a mixture A;

(4) adding 0.002mol of selenium powder and 0.002mol of sulfur powder into 4.2ml of hydrazine hydrate, and stirring until the selenium powder and the sulfur powder are completely dissolved to obtain a mixture B;

(5) dropwise adding the mixture B into the mixture A, uniformly stirring, transferring to a microwave reaction kettle, and carrying out microwave solvothermal reaction in a microwave hydrothermal synthesizer, wherein the method specifically comprises the following steps: heating to 175 ℃ with the heating power of 300w, and preserving the heat for 22min at the temperature to obtain a microwave solvent thermal product;

(6) transferring the microwave solvent thermal product into a stainless steel autoclave, carrying out solvent thermal reaction for 5h in an oven at the temperature of 170 ℃, centrifuging, washing and freeze-drying the obtained product (the process parameters are the same as those in the step (1)) to obtain MXene/SnSe_0.5S_0.5A composite material.

Example 5

(1) 2.5g of Ti₃AlC₂Adding into 67ml HF water solution with mass percent of 42% at the speed of 0.25g/min, stirring for 15h at the speed of 750r/min at 72 ℃ under the condition of water bath, centrifuging and washing the obtained etching solution,placing the obtained product in a culture dish, adding a small amount of deionized water, stirring until the product is completely dispersed uniformly, placing in a freeze dryer, freezing at-35 ℃ for 7h, vacuumizing, and drying at 45 ℃ for 5h to obtain a dry powdery etching product;

(2) adding 80mg of hydrazine hydrate into 87.5ml of dilute hydrochloric acid solution with the concentration of 0.8mol/L, and stirring at the stirring speed of 750r/min for 25min to obtain a layer expanding agent; adding the etching product obtained in the step (1) into the layer expanding agent, carrying out ultrasonic treatment for 58.5h at the temperature of 45 ℃, centrifuging, washing and freeze-drying the obtained product (the process parameters are the same as those in the step (1)) to obtain a layer expanding product;

(3) adding 87.5mg of the layer expanding product obtained in the step (2) into 42.5ml of ethylene glycol, performing ultrasonic dispersion for 2.5 hours, and then adding 0.008mol of SnCl₂·2H₂O, stirring for 75min to obtain a mixture A;

(4) adding 0.004mol of selenium powder and 0.004mol of sulfur powder into 6.7ml of hydrazine hydrate, and stirring until the selenium powder and the sulfur powder are completely dissolved to obtain a mixture B;

(5) dropwise adding the mixture B into the mixture A, uniformly stirring, transferring to a microwave reaction kettle, and carrying out microwave solvothermal reaction in a microwave hydrothermal synthesizer, wherein the method specifically comprises the following steps: heating to 205 ℃ with the heating power of 300w, and preserving the heat for 48min at the temperature to obtain a microwave solvent thermal product;

(6) transferring the microwave solvothermal product into a stainless steel autoclave, carrying out solvothermal reaction for 10 hours in an oven at the temperature of 190 ℃, centrifuging, washing and freeze-drying the obtained product (the process parameters are the same as those in the step (1)), and obtaining MXene/SnSe_0.5S_0.5A composite material.

Comparative example 1

The preparation method of the MXene negative electrode material comprises the following steps:

(1) 3.0g of Ti₃AlC₂Adding the mixture into 75ml of HF aqueous solution with the mass percent of 45% at the speed of 0.3g/min, stirring for 18 hours at the speed of 900r/min at the temperature of 80 ℃ under the condition of water bath, centrifuging and washing the obtained etching solution, placing the obtained product into a culture dish, adding a small amount of deionized water, and stirring until the product is completely and uniformly dispersedThen placing the mixture in a freeze dryer, freezing the mixture for 9 hours at the temperature of minus 30 ℃, and then vacuumizing the mixture and drying the mixture for 7 hours at the temperature of 40 ℃ to obtain a dry powdery etching product;

(2) adding 100mg of dopamine hydrochloride into 100ml of 1.0mol/L diluted hydrochloric acid solution, and stirring at the stirring speed of 900r/min for 30min to obtain a spreading agent; and (3) adding the etching product obtained in the step (1) into the layer expanding agent, carrying out ultrasonic treatment for 72h at the temperature of 50 ℃, centrifuging, washing and freeze-drying the obtained product (the process parameters are the same as those in the step (1)), so as to obtain a layer expanding product, namely the MXene negative electrode material.

Comparative example 2

(1) 3.0g of Ti₃AlC₂Adding the mixture into 75ml of HF aqueous solution with the mass percent of 45% at the speed of 0.3g/min, stirring for 18 hours at the speed of 900r/min at the temperature of 80 ℃ under the condition of water bath, centrifuging and washing the obtained etching solution, placing the obtained product into a culture dish, adding a small amount of deionized water, stirring until the product is completely and uniformly dispersed, placing the product into a freeze dryer, freezing for 9 hours at the temperature of-30 ℃, and then vacuumizing and drying for 7 hours at the temperature of 40 ℃ to obtain a dry powdery etching product;

(2) adding 100mg of dopamine hydrochloride into 100ml of deionized water, and stirring at the stirring speed of 900r/min for 30min to obtain a layer expanding agent; and (3) adding the etching product obtained in the step (1) into the layer expanding agent, carrying out ultrasonic treatment for 72h at the temperature of 50 ℃, centrifuging, washing and freeze-drying the obtained product (the process parameters are the same as those in the step (1)), so as to obtain a layer expanding product, namely the MXene negative electrode material.

Comparative example 3

SnSe_0.5S_0.5The preparation method of the anode material comprises the following steps:

(1) adding 0.01mol of SnCl₂·2H₂Adding O into 50ml of ethylene glycol, and stirring for 90min to obtain a mixture A;

(2) adding 0.005mol of selenium powder and 0.005mol of sulfur powder into 8ml of hydrazine hydrate, and stirring until the selenium powder and the sulfur powder are completely dissolved to obtain a mixture B;

(3) dropwise adding the mixture B into the mixture A, uniformly stirring, transferring to a microwave reaction kettle, and carrying out microwave solvothermal reaction in a microwave hydrothermal synthesizer, wherein the method specifically comprises the following steps: heating to 220 ℃ with the heating power of 300w, and preserving the heat for 60min at the temperature to obtain a microwave solvent thermal product;

(4) transferring the microwave solvent thermal product into a stainless steel autoclave, carrying out solvent thermal reaction for 12h in an oven at the temperature of 200 ℃, centrifuging and washing the obtained product, putting the obtained product into a culture dish, adding a small amount of deionized water, stirring until the product is completely dispersed uniformly, putting the product into a freeze dryer, freezing for 9h at the temperature of-30 ℃, vacuumizing, and drying for 7h at the temperature of 40 ℃ to obtain dry powdered SnSe_0.5S_0.5A material.

Comparative example 4

(2) adding 100mg of dopamine hydrochloride into 100ml of 1.0mol/L diluted hydrochloric acid solution, and stirring at the stirring speed of 900r/min for 30min to obtain a spreading agent; adding the etching product obtained in the step (1) into the layer expanding agent, carrying out ultrasonic treatment for 72 hours at the temperature of 50 ℃, centrifuging, washing and freeze-drying the obtained product (the process parameters are the same as those in the step (1)) to obtain a layer expanding product;

(5) dropwise adding the mixture B into the mixture A, uniformly stirring, transferring to a stainless steel autoclave, carrying out solvothermal reaction for 13h in an oven at the temperature of 200 ℃, centrifuging, washing and freeze-drying the obtained product (the process parameters are the same as those in the step (1)), so as to obtain MXene/SnSe_0.5S_0.5A composite material.

Examples of the experiments

MXene/SnSe obtained in examples 1 to 5_0.5S_0.5The composite material is mixed with a conductive agent and a binder to prepare a negative plate, the negative plate and the treated sodium plate are assembled to form the CR2032 button type sodium ion battery, and MXene/SnSe is prepared by testing each embodiment_0.5S_0.5The composite material is at 500mA g^-1Current density of (a) and cycle performance of the battery after 50 cycles, as shown in table 1. The results of the tests of example 1 vs. comparative example 1 are shown in fig. 4.

TABLE 1 MXene/SnSe obtained in the examples of the present application_0.5S_0.5Battery cycle performance of composite materials

Table 1 shows that the nano-scale SnSe prepared in the examples 1-5_0.5S_0.5The composite negative electrode with MXene is 500 mA.g^-1The reversible capacity after circulating for 50 circles under the current density is more than 640 mAh.g^-1Wherein the reversible capacity of the electrode material obtained in the example 1 can reach 667mAh g at most^-1As shown in fig. 4. This value is much higher than pure SnSe_0.5S_0.5(comparative example 3) with MXene alone (comparative example 1) after treatment with a layer-extending agent according to the present application, and with a composition comprising only-NH₂Organic based as MXene as a layer extender (comparative example 2). The result shows that the effect of treating MXene by using the coating agent is better, and the high-performance negative electrode material for the sodium-ion battery can be obtained by the microwave-assisted solvothermal method and the traditional solvothermal method. If only the traditional solvothermal method is adopted to obtain MXene and SnSe_0.5S_0.5Composite material of(comparative example 4), the reversible capacity of the composite negative electrode after 50 cycles was maintained at 515mAh g only^-1Far from MXene/SnSe prepared by the examples of the application_0.5S_0.5And (4) compounding the negative electrode.

It is noted that, in the present application, relational terms such as first, second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

All the embodiments in the present specification are described in a related manner, and the same and similar parts among the embodiments may be referred to each other, and each embodiment focuses on the differences from the other embodiments.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall fall within the protection scope of the present invention.

Claims

1.MXene/SnSe_0.5S_0.5The preparation method of the composite material is characterized by comprising the following steps:

step 1: MAX is mixed at a ratio of 1.0 g-3.0 g: adding 25-75 ml of the etching solution into 35-45 wt% of HF aqueous solution, stirring at the speed of 300-900 r/min for 6-18 h at the temperature of 50-80 ℃ under the condition of water bath, and centrifuging, washing and freeze-drying the obtained etching solution to obtain an etching product;

step 2: organic matter containing amino groups is mixed according to the mass volume ratio of 20 mg-100 mg: adding 50 ml-100 ml of diluted hydrochloric acid solution with the concentration of 0.2 mol/L-1.0 mol/L, and stirring at the stirring speed of 300 r/min-900 r/min for 10 min-30 min to obtain a layer expanding agent; the volume ratio of the HF aqueous solution obtained in the step (1) to the dilute hydrochloric acid solution obtained in the step (2) is 1-3: 2-4, the etching product obtained in the step (1) is added into the layer expanding agent, ultrasonic treatment is carried out for 18-72 h at the temperature of 30-50 ℃, and the obtained product is centrifuged, washed and freeze-dried to obtain a layer expanding product; the organic matter containing amino groups comprises any one of hydrazine hydrate, ethylenediamine and dopamine hydrochloride;

step 31: and (3) enabling the layer expanding product obtained in the step (2) to be mixed according to the mass volume ratio of 50-100 mg: adding 20 ml-50 ml of the mixture into ethylene glycol, ultrasonically dispersing for 1 h-3 h, and then adding SnCl₂·2H₂O, stirring for 30-90 min to obtain a mixture A; the SnCl₂·2H₂The molar volume ratio of O to glycol is 0.002 mol-0.01 mol: 20ml to 50 ml;

step 32: adding selenium powder and sulfur powder into a reducing solvent according to the molar ratio of 1:1, and stirring until the selenium powder and the sulfur powder are completely dissolved to obtain a mixture B; the reducing solvent is hydrazine hydrate; the selenium powder, the sulfur powder and the SnCl obtained in the step 31₂·2H₂The molar ratio of O is 1:1: 2;

step 33: dropwise adding the mixture B into the mixture A, uniformly stirring, transferring to a microwave reaction kettle, carrying out microwave solvothermal reaction in a microwave hydrothermal synthesizer, heating to 160-220 ℃ at the heating power of 300w, and preserving heat at the temperature for 10-60 min to obtain a microwave solvothermal product;

2. MXene/SnSe according to claim 1_0.5S_0.5Composite materialThe preparation method of (1), wherein in step 1, the MAX is Ti₃AlC₂The MAX is added at a rate of 0.1g/min to 0.3 g/min.

3. MXene/SnSe according to claim 1_0.5S_0.5The preparation method of the composite material is characterized in that in the step 32, the molar volume ratio of the selenium powder to the reducing solvent is 0.001-0.005 mol: 3ml to 8 ml.

4.MXene/SnSe_0.5S_0.5A composite material produced by the production method according to any one of claims 1 to 3.

5. The MXene/SnSe of claim 4_0.5S_0.5The composite material is applied to the field of preparing battery cathode materials.