CN106058206A - Composite material of flower-like carbon-supported MoS2 nanoparticles and its preparation method and application - Google Patents

Abstract

The invention belongs to the field of energy storing materials, in particular to a composite material for flower-like carbon-loaded MoS2 nanoparticles and a preparation method and application thereof. The preparation method comprises the following steps: performing high-temperature thermal treatment and acid etching by taking flower-like ZnO as a template and taking biomass as a precursor through a simple hydrothermal method to obtain a flower-like carbon substrate; performing solvent thermal treatment on flower-like carbon and ammonium tetrathiomolybdate to obtain the composite material in which the MoS2 nanoparticles are uniformly loaded on the flower-like carbon. The prepared composite material has high energy storing capacity, superior cycling stability and superior rate capability when being taken as a negative electrode material of a lithium battery. Biomass with a wide source is taken as the flower-like precursor, and a hydrothermal and solvent-thermal two-step method is adopted; the composite material has the advantage of easiness in operation, low production cost, low environmental pollution, easiness in bath production and large-scale production, good industrial production basis and wide application prospect.

Description

A kind of flower-shaped carbon-supported MoS2 nanoparticle composite material and its preparation method and application

technical field

The invention belongs to the technical field of energy storage materials, and in particular relates to a lithium battery negative electrode material and a preparation method and application thereof.

Background technique

In the past decade, the rapid development of wearable electronic devices as well as electric vehicles has led to a large demand for lithium battery materials with high energy storage capacity and excellent cycle stability. However, the theoretical energy storage capacity of traditional commercial graphite electrodes is only 372 mAh g ^-1 , which is difficult to meet the rapidly growing demand for energy storage. Recently, molybdenum disulfide, as a typical chalcogenide transition metal compound, has attracted extensive attention due to its special two-dimensional S-Mo-S three-layer structure. Molybdenum disulfide is further stacked by these two-dimensional sheets through weak van der Waals force, and the distance between the sheets is much larger than that of graphite electrodes (0.65 nm), so it is very suitable for intercalation storage of lithium ions. Theoretical calculations suggest that the theoretical capacity of molybdenum disulfide can reach 670 mAh g ^-1 , but their cycle stability and rate performance are still unsatisfactory due to problems such as poor conductivity and easy agglomeration during charge and discharge.

In order to solve these problems, a large number of researches are mainly devoted to compounding nano molybdenum disulfide with various conductive substrates to obtain nanocomposites. These conductive matrices can not only enhance the charge transfer between nanomolybdenum disulfide and the current collector, but also effectively inhibit the agglomeration of molybdenum disulfide and buffer its large volume change during charge and discharge. Among them, graphene-based carbon materials are the most widely used conductive substrates, because graphene-based conductive substrates generally have high electronic conductivity, good flexibility and high chemical stability. Therefore, a large number of composite materials of molybdenum disulfide-graphene-based carbon matrix, such as loading nano-molybdenum disulfide particles on graphene airgel (ACS appl. Mater. Interfaces, 2016, 8, 3320), graphene foam (Adv . Funct. Mater., 2013, 23, 5326), carbon nanotubes (ACS appl. Mater. Interfaces, 2016, 8, 1398) and graphene paper (Nanoscale, 2016, 8, 8042) have been reported extensively.

Although conductive carbon matrices with various structures based on graphene or carbon nanotubes are widely used to support molybdenum disulfide in situ, the preparation process of these graphene derivatives is relatively complicated and costly, and due to strong acid and strong oxidant The use of it will also pollute the surrounding environment. Because it is very meaningful to develop a flexible method to prepare carbon matrix materials. Recently, biomass, as a renewable and naturally abundant resource, has received increasing attention for the preparation of carbon materials. Hydrothermal is one of the most widely adopted methods for converting these biomasses because of its low cost, environmental friendliness and ease of operation. By heat-treating the hydrothermally carbonized biomass at high temperature, the carbonization and graphitization of the hydrothermal carbon can be further accelerated, thereby significantly improving the electrical conductivity of the material. Previous work has shown that the composite of biomass-based carbon materials and nano-molybdenum disulfide can effectively improve the electrochemical performance of molybdenum disulfide. For example, Luo et al. synthesized a composite material in which molybdenum disulfide nanosheets were grown in situ on the surface of carbon spheres formed by glucose hydrothermal treatment. They found that the introduction of carbon spheres could significantly improve the cycle stability of molybdenum disulfide (Chem. Eur. J., 2014, 20, 5219). In addition, cao et al. reported that the in situ coating of a glucose-based carbon layer on the surface of molybdenum disulfide with a flower-like structure can also improve the lithium storage performance of molybdenum disulfide (J. Mater. Chem. A, 2014, 2, 7862). However, there are still some limitations in these works, such as insufficient charge transfer and limited contact area between materials and electrolyte. Building a three-dimensional multi-level structure has been proved by a large number of experiments to be an effective strategy to solve the above problems.

This work is based on this idea to prepare a composite material in which molybdenum disulfide nanoparticles are grown on flower-like carbon materials in situ. First, we used zinc oxide as a hard template to obtain a porous flower-like carbon matrix by hydrothermal treatment with glucose combined with high-temperature annealing and acid etching. Molybdenum disulfide nanoparticles were grown in situ on the surface of the flower-like carbon matrix by solvothermal method to obtain the final nanocomposite material. Due to the unique three-dimensional flower-like structure, FC-MoS2 composites used as anode materials for lithium batteries have high reversible capacity (1033 mAhg ^{-1 in the second cycle at a current density of 0.2A g -1 )} , excellent Excellent cycle stability (958 mAh g ^-1 capacity after 50 cycles) and good rate capability.

Contents of the invention

The purpose of the present invention is to provide a low-cost, environmentally friendly and excellent energy storage performance flower-shaped carbon _- loaded MoS2 nanoparticle nanocomposite material and its preparation method and application.

The present invention provides a nanocomposite material in which MoS ₂ nanoparticles are supported on flower-like carbon, and MoS ₂ nanoparticles are grown in situ on the surface of flower-like carbon by a solvothermal method. The introduction of conductive flower _- like carbon can not only effectively improve the electron transfer ability of the material, but also inhibit the agglomeration of MoS2 and expand the contact area with the electrolyte, thereby obtaining a good energy storage effect.

The preparation method of the nano-composite material of flower-shaped carbon supported _{MoS2nanoparticles} provided by the invention, the specific steps are:

(1) Disperse 50-500 mg of synthetic flower-like ZnO in 5-20 ml deionized water, sonicate for 5-20 min, then add 50-500 mg of a certain biomass, and sonicate for 5-15 min; then the mixture Transfer to an autoclave, and place it in an oven at 120-250°C for 8-24 h; after cooling down to room temperature naturally, take out the product and wash it repeatedly with absolute ethanol for 3-8 times; then place the product at 50-150 Dry in an oven at ℃ for 2-24 h to form a powder;

(2) Take 0.1-1.0 g of dried powder and place it in a tube furnace, heat it to 400-1000 °C at a heating rate of 2-10 °C/min under the protection of nitrogen, and keep it for 1-5 h; Cool to room temperature; then treat the heat-treated material with 0.5-5M HCl for 0.5-6 h, then wash it with deionized water and ethanol for several times, and dry it in an oven at 50-150°C to obtain flower-shaped carbon;

(3) Weigh 5~50 mg of ammonium tetrathiomolybdate and add it to 10 ml of solvent, sonicate for 5~60 min to fully dissolve the ammonium tetrathiomolybdate; min to aid dispersion; add 0.1~1.0 ml of hydrazine monohydrate, then transfer the mixture to an autoclave, and place it in an oven at 100~250°C for 6~24 hours; after naturally cooling to room temperature, take out the liquid for use Centrifugal washing with deionized water for 3-10 times; then the product was dried in a vacuum oven at 30-120°C for 2-24 h, and then heat-treated in a tube furnace at 500-800°C under nitrogen protection for 1-5 h to obtain The final flower-like carbon _- supported composite of MoS2 nanoparticles.

In the present invention, the biomass used in step (1) is one of cellulose, glucose, chitosan, or a mixture of several of them;

In the present invention, the solvent used in step (3) is one of N,N-dimethylformamide, acetone, tetrahydrofuran, or a mixed solvent of several of them.

_The nanocomposite material in which MoS2 nanoparticles are supported on the flower-like carbon prepared by the present invention is realized by a simple two-step method of hydrothermal and solvothermal. Firstly, using biomass as carbon precursor and flower-like ZnO as template, three-dimensional porous flower-like carbon was obtained by hydrothermal method followed by high-temperature annealing and acid etching. Then, flower-like carbon was used as the substrate, and the composite material of MoS ₂ nanoparticles supported by flower-like carbon was obtained by solvothermal treatment with ammonium tetrathiomolybdate. As an anode material for lithium batteries, this material exhibits excellent electrochemical energy storage properties: high reversible capacity, excellent cycle stability, high current tolerance and recovery. This is because the introduction of flower _- like carbon can not only enhance the electronic conductivity of the material, but also effectively inhibit the agglomeration of MoS2 and expand the contact area with the electrolyte. _In addition, the strong interaction between the like carbon and MoS2 can also effectively buffer the large structural stress of _MoS2 during the charging and discharging process.

The invention has the advantages of convenient operation, simple preparation conditions, low production cost, environmental protection, easy batch and large-scale production, good industrial production basis and broad application prospect.

Description of drawings

Figure 1. Scanning electron micrograph (a) and transmission electron micrograph (b) of flower-like carbon.

Fig. _2. SEM images of flower-like carbon-supported MoS2 nanoparticle composites obtained by adding 22 mg ammonium tetrathiomolybdate.

Figure 3. Transmission electron micrographs of flower-like carbon _- supported MoS2 nanoparticle composites obtained by adding 22 mg ammonium tetrathiomolybdate.

Figure 4. The charge-discharge cycle performance of flower-like carbon _- supported MoS2 nanoparticle composites and pure MoS2 obtained by adding 22 mg ammonium tetrathiomolybdate at ₂₀₀ mA g ^-1 .

Figure 5. Charge-discharge rate performance of flower-like carbon _- supported MoS2 nanoparticle composites obtained by adding 22 mg ammonium tetrathiomolybdate at different current densities.

Fig. 6. Scanning electron micrograph (a) and transmission electron micrograph (b ₎ of pure MoS obtained by solvothermal ammonium tetrathiomolybdate.

Figure 7. SEM image (a) and transmission electron microscope image (b) of flower-like carbon-supported MoS ₂ nanoparticle composites obtained by adding 10 mg ammonium tetrathiomolybdate.

Fig. 8. Scanning electron micrograph (a) and transmission electron micrograph (b) of the flower-like carbon-supported MoS ₂ nanoparticle composite obtained by adding 40 mg ammonium tetrathiomolybdate.

detailed description

The preparation method and hydrogen evolution catalytic performance of the flower-shaped carbon-supported MoS ₂ nanoparticle composite material of the present invention will be further described in detail through the following examples. The examples are only for illustration rather than limitation of the present invention.

Example 1

(1) Disperse 100 mg of the synthesized flower-like ZnO in 10 ml of deionized water, sonicate for 20 min, then add 100 mg of glucose, and sonicate for 10 min; then transfer the mixture to a pressure furnace and place it in an oven at 180°C for reaction 12 h; after naturally cooling to room temperature, the product was taken out and centrifuged and washed 5 times with absolute ethanol; then the product was dried in an oven at 60°C for 6 h.

(2) Take 1.0 g of dried powder and place it in a tube furnace, heat it to 800 °C for 2 h at a heating rate of 5 °C/min under the protection of nitrogen; finally cool it to room temperature under the protection of gas. Then the heat-treated material was treated with 2 M HCl for 1 h, then centrifuged with deionized water and ethanol for several times, and dried in an oven at 60 °C to obtain flower-like carbon.

(3) Weigh 22 mg of ammonium tetrathiomolybdate and add it to 10 ml of DMF, sonicate for 10 minutes to fully dissolve the ammonium tetrathiomolybdate; then add 10 mg of flower-like carbon, and sonicate for 30 minutes to help disperse; add 0.1 ml Hydrazine monohydrate, then transfer the mixed solution to an autoclave, and place it in an oven at 200°C for 18 h; after cooling down to room temperature naturally, take out the material solution and wash it with deionized water for 6 times; then place the product at 60 ℃ in a vacuum oven for 6 h, and then heat-treated in a tube furnace at 500 °C for 2 h under nitrogen protection to obtain the final flower-like carbon-supported MoS ₂ nanoparticle composite.

It can be seen from Figure 1 that the flower-like carbon presents a three-dimensional structure and contains some large pores. After solvent heat treatment with 22 mg ammonium tetrathiomolybdate, it can be seen from the scanning electron micrograph in Figure 2 that the surface of the flower-like carbon is indeed uniformly loaded with a large number of MoS ₂ nanoparticles. The transmission electron microscope image in Figure 3 further proves the loading of MoS ₂ nanoparticles on the surface of the flower-like carbon, and the high-resolution transmission image shows that the size of the MoS ₂ crystals is very small (less than 10 nm), and there is a gap between the MoS 2 crystals and the matrix. have a better interaction. From the charge-discharge cycle stability diagram in Figure 4, it can be seen that the lithium battery characteristic capacity and cycle stability of the composite material added with flower-like carbon are significantly higher _than those of pure MoS2 nanoparticles, indicating that flower _- like carbon can improve the battery life of MoS2. Chemical energy storage performance. Figure 5 further shows that the composite material with flower-shaped carbon has excellent high current tolerance, and also has very good capacity recovery when returning to low current.

Example 2

Weigh 40 mg of ammonium tetrathiomolybdate and add it to 10 ml of DMF, ultrasonicate for 10 min to fully dissolve the ammonium tetrathiomolybdate; add 0.1 ml of hydrazine monohydrate, then transfer the mixture to a pressure vessel, place ℃ oven for 18 h; after natural cooling to room temperature, the material liquid was taken out and washed with deionized water for 6 times; Heat treatment for 2 h under the protection of nitrogen in the furnace to obtain the final MoS2 nanoparticle _hydrogen evolution catalytic material.

It can be seen from Figure 6 that the ammonium tetrathiomolybdate self-solvothermally obtains a nano-flower-like structure.

Example 3

(1) Disperse 100 mg of the synthesized flower-like ZnO in 10 ml of deionized water, sonicate for 20 min, then add 100 mg of glucose, and sonicate for 10 min; then transfer the mixture to a pressure furnace and place it in an oven at 180°C for reaction 24 h; after naturally cooling to room temperature, the product was taken out and washed with absolute ethanol for 5 times; then the product was dried in an oven at 60°C for 6 h.

(2) Take 1.0 g of dried powder and place it in a tube furnace, heat it to 800 °C for 2 h at a heating rate of 5 °C/min under the protection of nitrogen; finally cool it to room temperature under the protection of gas. Then the heat-treated material was treated with 2 M HCl for 1 h, then centrifuged with deionized water and ethanol for several times, and dried in an oven at 60 °C to obtain flower-like carbon.

Example 4

(1) Disperse 100 mg of the synthesized flower-like ZnO in 10 ml of deionized water, sonicate for 20 min, then add 100 mg of glucose, and sonicate for 10 min; then transfer the mixture to a pressure furnace and place it in an oven at 180°C for reaction 24 h; after naturally cooling to room temperature, the product was taken out and washed with absolute ethanol for 5 times; then the product was dried in an oven at 60°C for 6 h.

(2) Take 1.0 g of dried powder and place it in a tube furnace, heat it to 800 °C for 2 h at a heating rate of 5 °C/min under the protection of nitrogen; finally cool it to room temperature under the protection of gas. Then the heat-treated material was treated with 2 M HCl for 1 h, then centrifuged with deionized water and ethanol for several times, and dried in an oven at 60 °C to obtain flower-like carbon.

(3) Weigh 10 mg of ammonium tetrathiomolybdate and add it to 10 ml of DMF, sonicate for 10 minutes to fully dissolve the ammonium tetrathiomolybdate; then add 10 mg of flower-shaped carbon, and sonicate for 30 minutes to help disperse; add 0.1 ml Hydrazine monohydrate, then transfer the mixed solution to an autoclave, and place it in an oven at 200°C for 18 h; after cooling down to room temperature naturally, take out the material solution and wash it with deionized water for 6 times; then place the product at 60 After drying in a vacuum oven at ℃ for 6 h, heat treatment in a tube furnace at 500 °C for 2 h under nitrogen protection to obtain the final composite material of MoS ₂ nanoparticles and flower-like carbon.

It can be seen from Figure 7 that the composite material obtained by adding 10 mg ammonium tetrathiomolybdate can see that MoS ₂ nanoparticles are sparsely distributed on the surface of the flower-like carbon.

Example 5

(1) Disperse 100 mg of the synthesized flower-like ZnO in 10 ml of deionized water, sonicate for 20 min, then add 100 mg of glucose, and sonicate for 10 min; then transfer the mixture to a pressure furnace and place it in an oven at 180°C for reaction 24 h; after naturally cooling to room temperature, the product was taken out and washed with absolute ethanol for 5 times; then the product was dried in an oven at 60°C for 6 h.

(2) Take 1.0 g of dried powder and place it in a tube furnace, heat it to 800 °C for 2 h at a heating rate of 5 °C/min under the protection of nitrogen; finally cool it to room temperature under the protection of gas. Then the heat-treated material was treated with 2 M HCl for 1 h, then centrifuged with deionized water and ethanol for several times, and dried in an oven at 60 °C to obtain flower-like carbon.

(3) Weigh 40 mg of ammonium tetrathiomolybdate and add it to 10 ml of DMF, sonicate for 10 minutes to fully dissolve the ammonium tetrathiomolybdate; then add 10 mg of flower-like carbon, and ultrasonicate for 30 minutes to help disperse; add 0.1 ml Hydrazine monohydrate, then transfer the mixed solution to an autoclave, and place it in an oven at 200°C for 18 h; after cooling down to room temperature naturally, take out the material solution and wash it with deionized water for 6 times; then place the product at 60 ℃ in a vacuum oven for 6 h, and then heat-treated in a tube furnace at 500 °C for 2 h under nitrogen protection to obtain the final flower-like carbon-supported MoS ₂ nanoparticle composite.

As can be seen from Figure 8, the composite material obtained by adding 40 mg ammonium tetrathiomolybdate can be seen to have a large number of free MoS ₂ nano-flower structures, and MoS ₂ has serious agglomeration.

Claims (5)

1. a flower-shaped carbon load MoS in situ₂The preparation method of the composite of nano-particle, it is characterised in that concretely comprise the following steps:

(1) the flower-shaped ZnO of 50 ~ 500 mg synthesis is dispersed in 5 ~ 20 ml deionized waters, ultrasonic 5 ~ 20 min, is subsequently adding 50 ~ 500 mg biomass, ultrasonic 5 ~ 15 min；Then mixed liquor is transferred in autoclave pressure, be placed in 120 ~ 250 DEG C of baking ovens Reaction 8 ~ 24 h；After naturally cooling to room temperature, product is taken out, is centrifuged repeatedly washing 3 ~ 8 times with dehydrated alcohol；To produce subsequently Thing is placed in 2-24 h in 50 ~ 150 DEG C of baking ovens and dries；

(2) powder taking 0.1 ~ 1.0 g drying is placed in tube furnace, under nitrogen protection with the heating rate of 2 ~ 10 DEG C/min It is heated to 400 ~ 1000 DEG C, is incubated 1 ~ 5 h；It is cooled to room temperature under nitrogen protection；By material after heat treatment with 0.5 ~ 5 M HCl processes 0.5-6 h, then uses deionized water and ethanol eccentric cleaning repeatedly, dries, obtain flower-shaped in 50 ~ 150 DEG C of baking ovens Carbon；

(3) weighing 5 ~ 50mg four thio ammonium molybdate and join in 10 ml solvents, ultrasonic 5 ~ 60 min make four thio ammonium molybdate abundant Dissolve；Being subsequently adding 2 ~ 20 flower-shaped carbon of mg, ultrasonic 10 ~ 120 min help dispersion；Add 0.1 ~ 1.0 ml mono-hydrazine hydrate, subsequently Mixed liquor is transferred in autoclave pressure, be placed in 100 ~ 250 DEG C of baking ovens reaction 6 ~ 24 h；After naturally cooling to room temperature, will material Liquid takes out, with deionized water centrifuge washing 3 ~ 10 times；Then product is placed in 2 ~ 24 h in 30 ~ 120 DEG C of vacuum drying ovens dry, then Heat treatment 1 ~ 5 h under nitrogen protection in the tube furnace of 500 ~ 800 DEG C, obtains final flower-shaped carbon load MoS₂Nano-particle is multiple Condensation material.

Preparation method the most according to claim 1, it is characterised in that biomass used in step (1) are cellulose, Portugal One in grape sugar, chitosan, or the most several mixture.

Preparation method the most according to claim 1, it is characterised in that solvent used in step (3) is N, N-dimethyl One in Methanamide, acetone, oxolane, or the most several mixed solvents.

4. the flower-shaped carbon that one kind is prepared by one of claim 1-3 preparation method load MoS in situ₂Being combined of nano-particle Material.

Flower-shaped carbon the most as claimed in claim 4 load MoS₂The composite of nano-particle answering as lithium cell cathode material With.