CN106384811A - Blue phosphorus/transition metal disulfide heterojunction anode material and preparation method thereof - Google Patents

Abstract

The invention relates to a blue phosphorus/transition metal disulfide heterojunction anode material and a preparation method thereof. The technical scheme adopted is: calculation and simulation based on the first principle method of density function theory, and screening of blue phosphorus/transition metal disulfide Heterojunction, and further designed the preparation method of the heterojunction; firstly, the transition metal disulfide was prepared by chemical vapor deposition; then the transition metal disulfide, white phosphorus powder and organic solvent were stirred and mixed evenly, and then centrifuged After the treatment, an annealing treatment is performed in a vacuum or an argon atmosphere to obtain a blue phosphorus/transition metal disulfide heterojunction anode material. The anode material prepared by the invention has good structural stability, electrical conductivity, flexibility, large lithium adsorption capacity and good electrical properties, simple preparation process, strong repeatability, high yield and low cost, and is suitable for industrialization Mass production.

Description

A kind of blue phosphorus/transition metal disulfide heterojunction anode material and its preparation method

technical field

The invention relates to the technical field of nanometer materials, and proposes a blue phosphorus/transition metal disulfide heterojunction anode material.

Background technique

Two-dimensional transition metal dichalcogenides (transition metal dichalcogenides, TMDs), the general chemical formula is MX ₂ , where M can be the main group IV, V, VI transition metal, X is the chalcogen elements S, Se, Te, such as MoS ₂ and NbS ₂ , have attracted extensive attention not only because of their unique electronic and catalytic properties, but also because of their band engineering tunability over a wide range by strain or vertical electric field.

Elemental phosphorus has four allotropes, namely: white phosphorus, red phosphorus, purple phosphorus and black phosphorus (BP). Since the experimental discovery of the two-dimensional material black phosphorus, Zhu et al. have further proposed another form of phosphorus that is only two atomic layers thick: blue phosphorus (BluePhosphorus, BlueP) [Zhen Zhu, and David Tománek, Semiconductor Layered BluePhosphorus: A Computational Study, Phys. Rev. Lett, 2014, 112(17): 176802]. BlueP has the same thermal stability as BP, and has excellent physical and chemical properties. The layered BlueP and MX ₂ are both hexagonal crystals with only 2% lattice mismatch, which is conducive to the construction of high-quality van der Waals heterojunctions. Moreover, both _BlueP and MX2 have a large specific surface area, so the _BlueP /MX2 van der Waals heterojunction can form a wrinkled surface, which provides a larger space for storing lithium ions. The research and development of "stir-fried dishes" prepared purely through experiments is blind, with high research costs and low research and development efficiency.

The present invention first builds the structure, adopts the first-principles calculation based on density functional to design the material formulation and microstructure, and systematically studies the structural stability and electronic structure improvement of various BlueP/MX ₂ van der Waals heterojunctions. Properties, mechanical properties, electrochemical properties of lithium adsorption, etc.; further screened to obtain a blue phosphorus/transition metal dichalcogenide heterojunction with good conductivity, mechanical flexibility and high lithium storage capacity; finally, through the unique low-dimensional The material preparation technology realizes the synthesis and preparation of high-performance BlueP/MX ₂ heterojunction materials.

Contents of the invention

In order to solve the time-consuming and time-consuming blind test research and development of "fried dishes", improve the efficiency of research and development, and reduce the cost of research and development, the present invention systematically studies the BlueP/MX ₂ heterojunction based on the first principle of density functional The structure stability, electronic structure modification, mechanical properties, electrochemical properties of lithium adsorption, etc., the formula calculation and microstructure design of the material are carried out, and a blue phosphorus/transition metal dichalcogenide heterojunction anode material and its According to the preparation method, the prepared material has good structural stability and mechanical flexibility as an anode material of a lithium ion battery, and meanwhile, its electrical performance is good.

A blue phosphorus/transition metal disulfide heterojunction anode material is composed of the following raw materials: transition metal oxide, white phosphorus powder, chalcogen nonmetal powder and organic solvent.

Among them, in terms of molar ratio, transition metal oxide: white phosphorus powder: chalcogen nonmetal powder: organic solvent = 2:1:7:16.

The chalcogen nonmetal powder is one of sulfur powder, selenium powder and tellurium powder.

The transition metal oxide is one of MoO ₃ , WO ₃ , NbO ₃ , and TaO ₃ .

The organic solvent is one or two of dimethyl sulfoxide, N, N-dimethylformamide, N-methylpyrrolidone and isopropanol.

The method for preparing the anode material, the specific steps are as follows:

(1) Weigh each material separately according to the formula ratio;

(2) Ultrasonic cleaning the glass substrate with acetone and alcohol in sequence, and then rinse the surface of the glass substrate with deionized water for 3-5 times;

(3) Place the glass substrate and transition metal oxide in the reaction chamber of plasma-enhanced chemical vapor deposition, evacuate to 3×10 ⁴ ~4×10 ⁴ Pa, and flow argon gas at a flow rate of 35-45 sccm; The chalcogenide nonmetal powder is converted into chalcogenide nonmetal vapor by heating to 450~990°C in a heating furnace; the temperature of the reaction chamber is heated to 650~950°C for 2~3h, and then heated to 750~1050°C for 4~6h ; At the same time, using argon gas to blow the obtained chalcogen nonmetal vapor into the reaction chamber, and continue to feed it until the end of heating; finally, a transition metal disulfide film is formed on the surface of the substrate;

(4) Cut off the transition metal dichalcogenide film from the glass substrate with a knife, and place it in a mortar and grind it slowly to powder;

(5) Stir the transition metal disulfide powder, white phosphorus powder and organic solvent obtained in step (4) for 2-20 hours to mix evenly, let stand for 8-10 hours, then centrifuge, filter, and wash with alcohol to obtain blue phosphorus/ heterojunction complexes of transition metal dichalcogenides;

(6) Annealing the product obtained in step (5) at 700-900°C in vacuum or argon atmosphere for 5-8 hours to obtain the blue phosphorus/transition metal disulfide heterogeneous junction anode material.

Compared with the prior art, the present invention has the following advantages:

(1) The present invention is based on the first-principles method of the density function theory, which avoids repeated experiments of blind "stir-fried dishes", carries out formula calculation of materials and microstructure design, and prepares a product with good structural stability by vapor deposition method. Van der Waals heterojunction-blue phosphorus/transition metal dichalcogenide heterojunction with high conductivity, conductivity, flexibility and large lithium adsorption capacity, and use it as an anode material for lithium-ion batteries;

(2) The present invention further proposes a method for preparing a low-dimensional blue phosphorus/transition metal dichalcogenide heterojunction flexible anode material with a controllable layer number. The number of layers is controlled by controlling the cutting and stirring time of transition metal disulfide powder, white phosphorus powder and organic solvent mixture in a mixing barrel equipped with a high-speed rotating cutter head. The longer the stirring time, the thinner the prepared blue phosphorus/transition metal dichalcogenide heterojunction material, and the corresponding fewer layers.

(3) The preparation process of the present invention is simple, highly repeatable, high yield, low cost, suitable for large-scale industrial production, and has significant social and economic benefits.

Description of drawings

Figure 1 is the energy band structure of single-layer blue phosphorus/NbS ₂ and blue phosphorus/TaS ₂ heterojunctions, where the Fermi level is set at 0eV.

Figure 2 shows the uniaxial stress-strain curves of (a) monolayer blue phosphorus/NbS ₂ and (b) blue phosphorus/TaS ₂ heterojunctions along the zigzag and armchair directions, respectively.

Fig. 3 is the XRD patterns of blue phosphorus/NbS ₂ and blue phosphorus/TaS ₂ heterojunction films.

detailed description

The present invention will be further described in detail below in conjunction with specific examples, and the protection content of the present invention is not limited to the following examples. All equivalent changes and modifications made according to the patent scope of the present invention shall fall within the scope of the present invention.

Example 1

A blue phosphorus/transition metal disulfide heterojunction anode material, the raw material composition of which is as follows: by molar ratio: NbO ₃ : white phosphorus powder: sulfur powder: dimethyl sulfoxide = 2:1:7:16.

Concrete preparation steps are as follows:

(1) Weigh NbO ₃ , white phosphorus, sulfur powder and dimethyl sulfoxide according to the proportion of the formula;

(2) Ultrasonic cleaning of the glass substrate with acetone solution to remove organic dirt on the surface of the glass substrate, and ultrasonic cleaning of the glass substrate with alcohol to remove acetone on the surface of the glass substrate, followed by rinsing with deionized water for 3 times;

(3) Place the glass substrate and NbO ₃ powder in the plasma-enhanced chemical vapor deposition reaction chamber, evacuate to 3×10 ⁴ Pa, pass high-purity protective gas Ar, and control the flow rate at 35 sccm; pass the sulfur powder through The heating furnace is heated to 450° C. into sulfur vapor; the sulfur vapor is blown into the reaction chamber in which the glass substrate and NbO powder are placed using a carrier gas _; the temperature of the reaction chamber is heated to a first preset temperature (650 ℃) and keep it for the first preset time (2h), at this time, the solid powder evaporates, so that the NbO ₃ powder reacts with the sulfur vapor to generate gaseous NbO _3-x and deposits on the substrate, wherein 0<x≤1, the specific reaction equation of this process is: NbO ₃ +S NbO _3-x +x/2SO ₂ ; heat the temperature of the reaction chamber to the second preset temperature (750°C) and keep it for the second preset time (4h), and continue to feed sulfur steam to make the sulfur The steam continues to react with NbO _3-x to form a layered NbS ₂ film on the substrate surface. The specific reaction equation of this process is: NbO _3-x +(7-x)/2S NbS ₂ +(3-x)/2SO ₂ ;

(4) Then put NbS ₂ powder, white phosphorus powder and dimethyl sulfoxide in a mixing bucket equipped with a rotating cutter head at a speed of 300r/min, cut and stir at room temperature for 20h, then stand for 8h, and then centrifuge and filter and cleaning to obtain blue phosphorus with a hexagonal structure based on _NbS2 , thereby making a single-layer blue phosphorus/ _NbS2 heterojunction composite;

(5) Finally, the blue phosphorus/NbS ₂ heterojunction composite prepared above was annealed in a vacuum atmosphere at 700°C for 5 hours to obtain blue phosphorus/NbS ₂ heterojunction with a controllable number of low-dimensional layers. Mass junction flexible anode materials.

Example 2

A blue phosphorus/transition metal disulfide heterojunction anode material, the raw material composition of which is as follows: by molar ratio: TaO ₃ : white phosphorus: sulfur powder: organic solvent = 2:1:7:16.

Wherein the organic solvent is: N, N-dimethylformamide:N-methylpyrrolidone=1:3 in molar ratio.

(1) Weigh each material of TaO ₃ , white phosphorus, sulfur powder, N, N-dimethylformamide and N-methylpyrrolidone mixed organic solvent according to the formula ratio;

(2) Ultrasonic cleaning of the glass substrate with acetone solution to remove organic dirt on the surface of the glass substrate, and ultrasonic cleaning of the glass substrate with alcohol to remove acetone on the surface of the glass substrate, followed by rinsing with deionized water for 3 times;

(3) Place the glass substrate and TaO ₃ powder in the plasma-enhanced chemical vapor deposition reaction chamber, evacuate to 4×10 ⁴ Pa, pass high-purity protective gas Ar, and control the flow rate at 45 sccm; pass the sulfur powder through The heating furnace is heated to 450° C. into sulfur vapor; the sulfur vapor is blown into the reaction chamber in which the glass substrate and TaO powder are placed using a carrier gas _; the temperature of the reaction chamber is heated to a first preset temperature (750 ℃) and keep for the first preset time (3h), at this time, the solid powder evaporates, so that the TaO ₃ powder reacts with the sulfur vapor to generate gaseous TaO _3-x and deposits on the substrate, wherein 0<x≤1, the specific reaction equation of this process is: TaO ₃ +S TaO _3-x +x/2SO ₂ ; heat the temperature of the reaction chamber to the second preset temperature (800°C) and keep it for the second preset time (5h), and continue to feed sulfur vapor, so that the sulfur The steam continues to react with TaO _3-x to form a layered TaS ₂ film on the substrate surface. The specific reaction equation of this process is: TaO _3-x +(7-x)/2S TaS ₂ +(3-x)/2SO ₂ ;

(4) Then put TaS ₂ powder, white phosphorus powder, N, N-dimethylformamide and N-methylpyrrolidone mixed organic solvent in a mixing bucket equipped with a high-speed rotating cutter head, cut and stir at room temperature for 10 hours, and statically Set for 8 hours, and then centrifuged, filtered and washed to obtain blue phosphorus with a hexagonal structure based on TaS ₂ , thereby preparing a five-layer blue phosphorus/TaS ₂ heterojunction complex.

(5) Finally, the blue phosphorus/TaS ₂ heterojunction composite prepared above was annealed at 750°C in a vacuum atmosphere, and the holding time was 7h to obtain a blue phosphorus/TaS ₂ heterojunction with a controllable layer number. anode material.

Example 3

A blue phosphorus/transition metal disulfide heterojunction anode material, the raw material composition of which is as follows: MoO ₃ : white phosphorus: tellurium powder: methanol = 2:1:7:16.

(1) Weigh each material of MoO ₃ , white phosphorus, tellurium powder and methanol according to the proportion of the formula;

(2) Ultrasonic cleaning of the glass substrate with acetone solution to remove organic dirt on the surface of the glass substrate, and ultrasonic cleaning of the glass substrate with alcohol to remove acetone on the surface of the glass substrate, followed by rinsing with deionized water for 5 times;

(3) Place the glass substrate and MoO ₃ powder in the plasma-enhanced chemical vapor deposition reaction chamber, evacuate to 3.5×10 ⁴ Pa, pass high-purity protective gas Ar, and control the flow rate at 45 sccm; pass the tellurium powder through The heating furnace is heated to 990°C to convert tellurium vapor; the tellurium vapor is blown into the reaction chamber with the glass substrate and MoO3 powder by using carrier gas _; the temperature of the reaction chamber is heated to the first preset temperature (950 °C) and keep it for the first preset time (3h), at this time, the solid powder evaporates, so that the MoO ₃ powder reacts with the tellurium vapor to generate gaseous MoO _3-x and deposits on the substrate, wherein 0<x≤1, the specific reaction equation of this process is: MoO ₃ +Te MoO _3-x +x/2TeO ₂ ; the temperature of the reaction chamber is heated to a second preset temperature (1050°C) and maintained for a second preset time (6h), and the tellurium vapor is continuously introduced to make the tellurium The steam continues to react with MoO _3-x to form a layered MoTe ₂ film on the substrate surface. The specific reaction equation of this process is: MoO _3-x +(7-x)/2Te MoTe ₂ +(3-x)/2TeO ₂ ;

(4) Then put MoTe ₂ powder, white phosphorus powder and isopropanol organic solvent in a mixing bucket equipped with a high-speed rotating cutter head, cut and stir for 4 hours at room temperature, let stand for 8 hours, and then centrifuge, filter and wash to obtain the following MoTe ₂ is the hexagonal blue phosphorus as the base, so that the blue phosphorus/MoTe ₂ composite with three-dimensional structure is prepared.

(5) Finally, the blue phosphorus/MoTe ₂ heterojunction composite prepared above was annealed in a vacuum atmosphere at 900°C for 8 hours to obtain a three-dimensional blue phosphorus/MoTe ₂ heterojunction anode material.

The present invention uses first-principle calculations based on density functional theory, and screens out a material with good electrical conductivity (the energy band passes through the Fermi level, as shown in Figure 1), mechanical flexibility (uniaxial ultimate tensile strain is 17%, ₂ ) and the blue phosphorus/NbS heterojunction with higher lithium adsorption capacity (528 mAhg ⁻¹ ), which is superior to that of graphene (372 mAhg ⁻¹ with an ultimate tensile strain of 15%). Moreover, the open circuit voltage of the BlueP/ _NbS2 heterojunction is always positive during the lithium ion adsorption process, as shown in Table 1. BlueP/NbS ₂ heterojunction is expected to be used as a flexible anode material for lithium batteries. In the XRD pattern, the sharper the peak, the better the crystallinity. Therefore, it can be seen from Figure 3 that the BlueP/NbS ₂ heterojunction presents the largest peak on the (002) plane, and the peak width is only 1°, and the other crystal planes all present small peaks or no peaks, indicating that BlueP/NbS ₂ The heterojunction has good crystallinity, which has good structural stability.

Table 1

The above descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

Claims (6)

1. a kind of indigo plant phosphorus/transition metal dichalcogenide hetero-junctions anode material it is characterised in that：It is made up of following raw material：Cross Cross metal-oxide, white phosphorus powder, sulfur family non-metal powder and organic solvent.

2. according to claim 1 a kind of indigo plant phosphorus/transition metal dichalcogenide hetero-junctions anode material it is characterised in that： According to the molar ratio, transition metal oxide：White phosphorus powder：Sulfur family non-metal powder：Organic solvent=2:1:7:16.

3. according to claim 1 a kind of indigo plant phosphorus/transition metal dichalcogenide hetero-junctions anode material it is characterised in that： Described sulfur family non-metal powder is sulphur powder, selenium powder, the one of which of tellurium powder.

4. according to claim 1 a kind of indigo plant phosphorus/transition metal dichalcogenide hetero-junctions anode material it is characterised in that： Described transition metal oxide is MoO₃、WO₃、NbO₃、TaO₃One of which.

5. according to claim 1 a kind of indigo plant phosphorus/transition metal dichalcogenide hetero-junctions anode material it is characterised in that： Described organic solvent is dimethyl sulfoxide, N,N-dimethylformamide, N-Methyl pyrrolidone and isopropanol one kind therein Or it is two or more.

6. a kind of prepare as claimed in claim 1 a kind of indigo plant phosphorus/transition metal dichalcogenide hetero-junctions anode material method, It is characterized in that：Comprise the following steps that：

（1）Weigh each material according to formula proportion respectively；

（2）With acetone, ethanol, glass substrate is cleaned by ultrasonic successively, then deionized water rinses glass substrate surface 3- 5 times；

（3）Glass substrate and transition metal oxide are placed in the reaction chamber of plasma enhanced chemical vapor deposition, take out true Empty to 3 × 10⁴~4×10⁴Pa, is passed through argon with 35 ~ 45sccm flow；Sulfur family non-metal powder is heated to by heating furnace 450 ~ 990 DEG C are changed into the nonmetallic steam of sulfur family；The temperature of described reaction chamber is heated to 650 ~ 750 DEG C of holding 2 ~ 3h, then plus Heat to 750 ~ 800 DEG C keeps 4 ~ 6h；Using argon, nonmetallic for gained sulfur family steam is blown into reaction chamber simultaneously, and be continually fed into Heating terminates；Finally form transition metal dichalcogenide thin film in described substrate surface；

（4）With pocket knife, lower transition metal dichalcogenide thin film is cut from glass substrate, be placed in mortar being slowly ground to powder；

（5）By step（4）Transition metal dichalcogenide powder, white phosphorus powder and the organic solvent obtaining stirs 2 ~ 20h mixing all Even, stand 8-10h, then by centrifugation, filtration, then with alcohol washes, obtain the hetero-junctions of blue phosphorus/transition metal dichalcogenide again Compound；

（6）By step（5）Prepared product, in vacuum or argon gas atmosphere, is made annealing treatment in 700 ~ 900 DEG C, annealing time For 5-8h, obtain described blue phosphorus/transition metal dichalcogenide hetero-junctions anode material.