阅读说明：本技术 一种石墨烯插层二硫化钼复合材料的制备及应用方法 (Preparation and application method of graphene intercalation molybdenum disulfide composite material ) 是由 刘永畅 李平 李省伟 曲选辉 于 2021-01-19 设计创作，主要内容包括：一种石墨烯插层二硫化钼复合材料的制备及应用方法。将商用二硫化钼浸泡在正丁基锂溶液中,氩气环境下搅拌,清洗,干燥,得到硫化钼锂,加水剧烈反应得到剥离二硫化钼分散液A。在A溶液中加入阳离子表面活性剂,单层氧化石墨烯分散液,二硫化钼层与氧化石墨烯层互相吸附；加入还原剂,水热处理,氧化石墨烯还原为石墨烯且伴随石墨烯嵌入二硫化钼层间；清洗,冷冻干燥,得到石墨烯插层二硫化钼复合材料。本发明的优点是：重复性好、反应条件易于控制。所得材料呈现“三明治”结构复合纳米片组装成的微米花,纳米片厚度为10-20nm,二硫化钼层间距扩大为1.16nm,亲水性良好,有利于水合锌离子的快速、稳定脱嵌,使得储锌容量,倍率性能和循环稳定性得到显著提升。(A preparation and application method of a graphene intercalation molybdenum disulfide composite material. Soaking commercial molybdenum disulfide in n-butyl lithium solution, stirring under an argon environment, cleaning, drying to obtain molybdenum lithium sulfide, and adding water to react violently to obtain the stripped molybdenum disulfide dispersion A. Adding a cationic surfactant, a single-layer graphene oxide dispersion liquid and a molybdenum disulfide layer into the solution A, and adsorbing the molybdenum disulfide layer and the graphene oxide layer mutually; adding a reducing agent, carrying out hydrothermal treatment, reducing graphene oxide into graphene, and embedding the graphene into a molybdenum disulfide layer; and cleaning, freezing and drying to obtain the graphene intercalation molybdenum disulfide composite material. The invention has the advantages that: good repeatability and easy control of reaction conditions. The obtained material is micro-flower assembled by composite nano sheets with a sandwich structure, the thickness of the nano sheets is 10-20nm, the distance between molybdenum disulfide layers is enlarged to 1.16nm, the hydrophilicity is good, and the rapid and stable de-intercalation of hydrated zinc ions is facilitated, so that the zinc storage capacity, the rate capability and the cycling stability are obviously improved.)

1. A preparation method of a graphene intercalation molybdenum disulfide composite material is characterized by comprising the following steps:

1) soaking commercial molybdenum disulfide into n-butyl lithium solution, continuously stirring for 4-6 days under an argon environment, then cleaning with anhydrous pentane, drying to obtain molybdenum lithium sulfide, and violently reacting with water under an ultrasonic condition to obtain uniform stripped molybdenum disulfide dispersion liquid A;

2) adding a cationic surfactant into the solution A, carrying out ultrasonic treatment for 1.5-2.5 hours, adding a single-layer graphene oxide dispersion solution into the solution, and carrying out ultrasonic treatment for 1.5-2.5 hours again to enable a molybdenum disulfide layer and a graphene oxide layer to be mutually adsorbed through electrostatic attraction to form a uniform solution B;

3) and adding a reducing agent into the solution B, transferring the mixed solution into a high-pressure reaction kettle with a polytetrafluoroethylene lining, carrying out hydrothermal treatment, cleaning, and freeze-drying to obtain the graphene intercalation molybdenum disulfide composite material.

2. The method for preparing the graphene intercalated molybdenum disulfide composite material according to claim 1, wherein the molar ratio of the commercial molybdenum disulfide to the n-butyllithium in the step 1) is 1: 2.

3. the preparation method of the graphene intercalation molybdenum disulfide composite material according to claim 1, wherein the preparation method of the n-butyl lithium solution in the step 1) comprises the following steps: adding anhydrous pentane to dilute the n-butyllithium solution with the concentration of 2.4mol/L to 1 mol/L.

4. The preparation method of the graphene intercalation molybdenum disulfide composite material according to claim 1, wherein the mass ratio of molybdenum lithium sulfide to water in the step 1) is 1: 150.

5. the preparation method of the graphene intercalation molybdenum disulfide composite material according to claim 1, wherein the preparation method of the cationic surfactant in the step 2) is as follows: 0.5mmol of hexadecyl trimethyl ammonium bromide is uniformly dissolved in 8mL of water; the preparation method of the single-layer graphene oxide dispersion liquid comprises the following steps: and (3) uniformly and ultrasonically dispersing 10-18mg of monolayer graphene oxide in 20mL of water.

6. The preparation method of the graphene intercalation molybdenum disulfide composite material according to claim 1, wherein the reducing agent in step 3) is 3mmol thiourea; the hydrothermal reaction temperature is 180 ℃ and the time is 6 hours.

7. The method for preparing the graphene intercalated molybdenum disulfide composite material according to claim 1, wherein the freeze drying in the step 3) is performed at a vacuum degree of 1.0Pa and a temperature of less than-45 ℃.

8. The application method of the graphene intercalation molybdenum disulfide composite material prepared by the method of claim 1 is characterized in that: preparing a graphene intercalation molybdenum disulfide composite material, conductive carbon black and a binder polyvinylidene fluoride (PVdF) according to a weight ratio of 70: 20: mixing the materials according to the mass ratio of 10, uniformly grinding the materials, coating the materials on a stainless steel mesh current collector, and drying the materials to prepare the anode plate of the water system zinc ion battery.

9. The application method of the graphene intercalation molybdenum disulfide composite material according to claim 8, characterized in that: an electrode plate made of a graphene intercalation molybdenum disulfide composite material, conductive carbon black and a binding agent polyvinylidene fluoride (PVdF) is used as a zinc ion battery anode, metal zinc is used as a counter electrode, a zinc trifluoromethanesulfonate aqueous solution with the concentration of 3mol/L is used as an electrolyte, glass fibers are used as a diaphragm, and a button battery with the model number of C2032 is assembled in an air environment.

Technical Field

The invention belongs to the technical field of water-based zinc ion batteries, and particularly relates to a preparation and application method of a graphene intercalation molybdenum disulfide composite material.

Background

In recent years, with the rapid development of smart grids and electronic products, the demand of human beings for intermittent renewable clean energy sources (such as solar energy, tidal energy, wind energy and geothermal energy) is increasing, and the development of large-scale energy storage devices is imperative. The water system zinc ion battery has great development prospect in the field of large-scale energy storage by virtue of the advantages of high safety, low cost, high theoretical capacity, convenient assembly and the like. However, the strong solvation of zinc ions and the strong electrostatic interaction of divalent charges with the positive electrode material limit the diffusion kinetics of zinc ions in the positive electrode material, resulting in a lower zinc storage capacity or poor cycling stability. Therefore, developing a suitable cathode material to satisfy the requirement of rapid and stable zinc ion deintercalation is one of the key points for promoting the development of aqueous zinc ion batteries.

The layered material is widely researched as a positive electrode of a water-based zinc ion battery due to a unique two-dimensional ion transmission channel, and particularly, vanadium-based and manganese-based oxides attract great interest of researchers. A large amount of structural water exists in the hydrated vanadium pentoxide, so that the electrostatic interaction between divalent zinc ions and a host material can be effectively shielded, the circulation performance is excellent, and the toxicity of the hydrated vanadium pentoxide can cause the risk of environmental pollution. The manganese-based oxide has higher zinc storage capacity, but the cycling stability is poor due to the structural evolution and material dissolution generated in the cycling process. Therefore, it is necessary to develop a positive electrode material for an aqueous zinc ion battery, which has high safety, high capacity, long cycle life, and environmental friendliness.

Molybdenum disulfide is taken as a classic two-dimensional layered material and is used in lithium ion batteries,The field of sodium ion batteries has been extensively studied, exhibiting good lithium and sodium storage capacity, but has rarely been developed as an aqueous zinc ion battery positive electrode due to poor hydrophilicity and small interlayer spacing. In prior studies, the interlayer spacing (h.li, q.yang, f.mo, et al.mos) was expanded₂nanosheets with extended interlayer spacing for retrievable aquouos Zn-ion batteries, Energy Storage Materials, 2019 (19): 94-101), oxygen doping (H.Liang, Z.Cao, F.Ming, et al₂by Tuning the interaction Energy, Nano Letters, 2019 (19): 3199-3206), making sulfur vacancies (W.Xu, C.Sun, K.ZHao, et al.Defect engineering activity of MOS)₂Energy Storage Materials, 2019 (16): 527-534) and the like, but the zinc storage site is insufficient, and the spatial structure is unstable, so that the reversible capacity and the cycling stability of the molybdenum disulfide anode can hardly meet the practical application requirements.

Disclosure of Invention

The invention provides a preparation method and an application method of a graphene intercalation molybdenum disulfide composite material. And (2) taking a cationic surfactant as a medium, enabling the stripped molybdenum disulfide layer and the oxidized graphene dispersion layer to be mutually adsorbed through electrostatic attraction, reducing the oxidized graphene into graphene through hydrothermal reduction, and embedding the graphene into the molybdenum disulfide layer along with the graphene to obtain the graphene intercalated molybdenum disulfide sandwich structure composite nanosheet. The interval between the molybdenum disulfide layers is enlarged to 1.16nm from 0.62nm, the thickness of the composite nanosheets is 10-20nm, the composite nanosheets are self-assembled into a micrometer flower skeleton, the re-accumulation of the molybdenum disulfide and the graphene can be effectively inhibited, the structural stability of the material is enhanced, meanwhile, the residual oxygen-containing functional groups in the reduced graphene oxide effectively improve the hydrophilicity, the full infiltration of electrolyte is facilitated, and the zinc storage capacity, the rate capability and the cycle life are obviously improved.

Based on the purpose, the invention adopts the following technical scheme:

a preparation method of a graphene intercalation molybdenum disulfide composite material comprises the following steps:

1) soaking commercial molybdenum disulfide in 1mol/L n-butyllithium solution, stirring for 4-6 days in an argon environment, then cleaning with anhydrous pentane, drying to obtain molybdenum lithium sulfide, and violently reacting with water under an ultrasonic condition to obtain uniform stripped molybdenum disulfide dispersion liquid A;

2) adding a cationic surfactant into the solution A, carrying out ultrasonic treatment for 1.5-2.5 hours, then adding a single-layer graphene oxide dispersion solution, and carrying out ultrasonic treatment for 1.5-2.5 hours again, so that a molybdenum disulfide layer and a graphene oxide layer are adsorbed by each other through electrostatic attraction to obtain a uniform solution B;

3) and adding a reducing agent into the solution B, transferring the mixed solution into a high-pressure reaction kettle, carrying out hydrothermal reaction for 6 hours at 180 ℃, and carrying out cleaning and freeze drying to obtain the graphene intercalation molybdenum disulfide sandwich structure composite nanosheet.

Further, the molar ratio of the molybdenum disulfide to the n-butyl lithium in the step (1) is 1: 2; the mass ratio of the molybdenum lithium sulfide to the water is 1: 150.

further, the preparation method of the cationic surfactant in the step (2) is as follows: 0.5mmol of hexadecyl trimethyl ammonium bromide is uniformly dissolved in 8mL of water; the preparation method of the single-layer graphene oxide dispersion liquid comprises the following steps: 10-18mg of monolayer graphene oxide is uniformly dispersed in 20mL of water.

Further, the reducing agent in the step (3) is 3mmol of thiourea; the freeze-drying is carried out at a vacuum of 1.0Pa and at a temperature below-45 ℃.

The application method of the graphene intercalated molybdenum disulfide composite material prepared by the method is characterized in that the graphene intercalated molybdenum disulfide composite material, conductive carbon black and a polyvinylidene fluoride (PVdF) binder are mixed according to the weight ratio of 70: 20: mixing the materials according to the mass ratio of 10, uniformly grinding the materials, coating the materials on a stainless steel mesh current collector, and drying the materials to prepare the anode plate of the water system zinc ion battery.

Further, an electrode slice prepared by mixing a graphene intercalation molybdenum disulfide composite material, conductive carbon black and a binding agent polyvinylidene fluoride (PVdF) is used as a positive electrode of the zinc ion battery, metal zinc is used as a counter electrode, a 3mol/L zinc trifluoromethanesulfonate aqueous solution is used as an electrolyte, glass fiber is used as a diaphragm, and the battery is assembled into a CR2032 button cell in an air environment.

Compared with the prior art, the invention has the advantages that:

the method has the advantages of easily controlled reaction conditions and high repetition rate, and can obtain the micrometer flower assembled by the graphene intercalation molybdenum disulfide composite nanosheets, wherein the thickness of the nanosheets is 10-20nm, and the interlayer spacing of molybdenum disulfide is enlarged to 1.16 nm. The graphene is inserted between the molybdenum disulfide layers, so that the hydrophilicity and the electronic/ionic conductivity of the material are improved, and the zinc storage capacity, the rapid charge and discharge capacity and the cycle life are obviously improved.

Drawings

Fig. 1 is an XRD pattern of graphene intercalated molybdenum disulfide composite material in example 1 of the present invention;

FIG. 2 is SEM, TEM and SEM Mapping images of the graphene intercalated molybdenum disulfide composite material in example 1 of the invention;

fig. 3 is a cycle performance diagram of the graphene intercalated molybdenum disulfide composite material as the positive electrode of the aqueous zinc ion battery in example 1 of the present invention.

Detailed Description

The present invention is further illustrated by the following examples.

Example 1:

1) taking 10.5mL of n-butyllithium solution with the concentration of 2.4mol/L, adding 15mL of anhydrous pentane to dilute the concentration of the n-butyllithium solution to 1mol/L, uniformly dispersing 2g of commercial molybdenum disulfide in the solution, continuously stirring for 5 days under an argon environment, then washing for three times by using the anhydrous pentane, and naturally drying for 2 days under a negative pressure condition to obtain molybdenum lithium sulfide; taking 100mg of molybdenum lithium sulfide, and violently reacting with 15mL of water for 3 hours under an ultrasonic condition to obtain uniform stripped molybdenum disulfide dispersion liquid A;

2) uniformly dissolving 0.5mmol of hexadecyl trimethyl ammonium bromide in 8mL of water, adding the solution A into the solution A, and keeping the solution for 2 hours under an ultrasonic condition; uniformly dispersing 14mg of single-layer graphene oxide in 20mL of water, adding the mixture into the mixed solution, and performing ultrasonic treatment again for 2 hours to enable the stripped molybdenum disulfide layer and the graphene oxide dispersion layer to be mutually adsorbed through electrostatic attraction, so as to obtain a uniform solution B;

3) and (3) uniformly dissolving 3mmol of thiourea in the solution B, transferring the mixed solution into a 50mL high-pressure reaction kettle, reacting for 6 hours at 180 ℃, cleaning with warm water, collecting black flocculent precipitate, and freeze-drying to obtain the graphene intercalation molybdenum disulfide composite material.

An electrode was prepared from the graphene intercalated molybdenum disulfide composite prepared in example 1 by the following method:

preparing a graphene intercalation molybdenum disulfide composite material, conductive carbon black and a binder polyvinylidene fluoride (PVdF) according to a weight ratio of 70: 20: mixing the components according to a mass ratio of 10, uniformly grinding the components, coating the ground components on a stainless steel mesh current collector, drying the components to prepare a zinc ion battery positive plate, taking metal zinc as a counter electrode, taking a zinc trifluoromethanesulfonate aqueous solution with the concentration of 3mol/L as an electrolyte, taking glass fiber as a diaphragm, and assembling the components into a CR2032 button battery in an air environment.

Fig. 1 is an XRD pattern of the graphene intercalated molybdenum disulfide composite material in example 1 of the present invention, and by comparison with a standard diffraction card, the (002) diffraction peak of molybdenum disulfide disappears, and two new diffraction peaks having a diploid relationship appear at 7.6 ° and 15.2 ° 2 θ, which indicates that graphene intercalates between layers of molybdenum disulfide and causes the interlayer spacing thereof to expand to 1.16 nm.

Fig. 2(a) is an SEM topography of the graphene intercalated molybdenum disulfide composite material in example 1 of the present invention: the graphene intercalation molybdenum disulfide composite nanosheets are self-assembled into flower-shaped structures, the structure is stabilized, electrolyte permeation is promoted, the thickness of the nanosheets is 10-20nm, and the nanosheets are uniformly distributed. (b) In an HRTEM of the graphene intercalated molybdenum disulfide composite material in embodiment 1 of the invention, the distance between molybdenum disulfide layers is enlarged to 1.16nm, and the embedding of single-layer graphene between the molybdenum disulfide layers can be clearly observed. (c) The element distribution diagram is SEM Mapping element distribution diagram, and C, Mo, S and O elements are uniformly distributed in the matrix of the graphene intercalation molybdenum disulfide composite material.

FIG. 3 is a graph of the cycle performance of the graphene intercalated molybdenum disulfide composite material as the anode of the aqueous zinc ion battery in example 1 of the invention, and the material is 0.2-1.5V (vs. Zn)²⁺Zn) voltage window of 0.05Ag^-1Initial at Current DensityReversible capacity up to 283.7mAh g^-1After 100 weeks of circulation, the reversible capacity was about 263.7mAh g^-1The capacity retention rate is as high as 93.0%. The reversible capacity and cycle stability are superior to other transition metal chalcogenides used as positive electrodes of aqueous zinc ion batteries.

Example 2:

1) taking 10.5mL of n-butyllithium solution with the concentration of 2.4mol/L, adding 15mL of anhydrous pentane to dilute the concentration of the n-butyllithium solution to 1mol/L, uniformly dispersing 2g of commercial molybdenum disulfide in the solution, continuously stirring for 5 days under an argon environment, then washing for three times by using the anhydrous pentane, and naturally drying for 2 days under a negative pressure condition to obtain molybdenum lithium sulfide; taking 100mg of molybdenum lithium sulfide, and violently reacting with 15mL of water for 3 hours under an ultrasonic condition to obtain uniform stripped molybdenum disulfide dispersion liquid A;

2) uniformly dissolving 0.5mmol of hexadecyl trimethyl ammonium bromide in 8mL of water, adding the solution A into the solution A, and keeping the solution for 2 hours under an ultrasonic condition; uniformly dispersing 10mg of single-layer graphene oxide in 20mL of water, adding the mixture into the mixed solution, and performing ultrasonic treatment again for 2 hours to enable the stripped molybdenum disulfide layer and the graphene oxide dispersion layer to be mutually adsorbed through electrostatic attraction, so as to obtain a uniform solution B;

3) and (3) uniformly dissolving 3mmol of thiourea in the solution B, transferring the mixed solution into a 50mL high-pressure reaction kettle, reacting for 6 hours at 180 ℃, cleaning with warm water, collecting black flocculent precipitate, and freeze-drying to obtain the graphene intercalation molybdenum disulfide composite material. Due to the reduced amount of graphene oxide added, the (001) and (003) diffraction peaks of molybdenum disulfide were stronger than those of the material prepared in example 1.

The graphene intercalated molybdenum disulfide composite material prepared in the example 2 is prepared into a CR2032 button cell by the method in the example 1.

Example 3:

1) taking 10.5mL of n-butyllithium solution with the concentration of 2.4mol/L, adding 15mL of anhydrous pentane to dilute the concentration of the n-butyllithium solution to 1mol/L, uniformly dispersing 2g of commercial molybdenum disulfide in the solution, continuously stirring for 5 days under an argon environment, then washing for three times by using the anhydrous pentane, and naturally drying for 2 days under a negative pressure condition to obtain molybdenum lithium sulfide; taking 100mg of molybdenum lithium sulfide, and violently reacting with 15mL of water for 3 hours under an ultrasonic condition to obtain uniform stripped molybdenum disulfide dispersion liquid A;

2) uniformly dissolving 0.5mmol of hexadecyl trimethyl ammonium bromide in 8mL of water, adding the solution A into the solution A, and keeping the solution for 2 hours under an ultrasonic condition; uniformly dispersing 18mg of single-layer graphene oxide in 20mL of water, adding the mixture into the mixed solution, and performing ultrasonic treatment again for 2 hours to enable the stripped molybdenum disulfide layer and the graphene oxide dispersion layer to be mutually adsorbed through electrostatic attraction, so as to obtain a uniform solution B;

3) and (3) uniformly dissolving 3mmol of thiourea in the solution B, transferring the mixed solution into a 50mL high-pressure reaction kettle, reacting for 6 hours at 180 ℃, cleaning with warm water, collecting black flocculent precipitate, and freeze-drying to obtain the graphene intercalation molybdenum disulfide composite material. Due to the fact that the addition amount of the graphene oxide is increased, part of molybdenum disulfide is coated by the graphene through a hydrothermal reduction process, and diffraction peaks (001) and (003) are weaker than those of the material prepared in example 1.

The graphene intercalated molybdenum disulfide composite material prepared in the example 3 is prepared into a CR2032 button cell by the method in the example 1.

Finally, it is to be noted that the above examples are only given to aid understanding of the method of the present invention and its core concept. Without limiting the scope of the invention, it will be appreciated by those skilled in the art that various modifications may be made to the invention in order to optimize the present invention. Any modifications and variations that may be made without departing from the principles of the invention are intended to be included within the scope of the following claims.