CN104124438B - A kind of flower-shaped nickelous sulfide-tellurium matrix material, preparation method and its usage - Google Patents

Abstract

The invention relates to a flower-shaped nickel sulfide-tellurium composite material, a preparation method and its application. The preparation method of the composite material is as follows: (1) dissolving the tellurium source precursor and the nickel source precursor in an organic solvent, and then adding an organic Sulfur compounds and weakly basic compounds are sealed and reacted under high pressure; (2) after the reaction is completed, the pressure is released to normal pressure, and naturally cooled to room temperature, centrifuged to obtain a solid, which is washed with water and absolute ethanol successively, vacuum drying to obtain the flower-shaped nickel sulfide-tellurium composite material. The nickel sulfide-tellurium composite material has good uniform and controllable morphology, good discharge capacity and cycle performance, and can be used in the field of lithium ion batteries.

Description

A flower-shaped nickel sulfide-tellurium composite material, its preparation method and its use

technical field

The invention provides a metal-nonmetal composite material, a preparation method and its application, more specifically, a flower-shaped nickel sulfide-tellurium composite material, a preparation method and its application, belonging to the field of inorganic composite materials.

Background technique

In the field of inorganic materials, nickel sulfide is an important functional material that can be widely used in infrared detectors, solar energy storage devices, hydrodesulfurization catalytic reactions, etc., as well as photoelectric conductive materials and electrode materials for rechargeable lithium batteries. For example, the specific application of nickel sulfide in many fields has been reported in the following prior art:

CN1281029A discloses a method for nickel sulfide-molybdenum-based hydrodesulfurization and dearsenization catalysts, in which the solid nickel sulfide-molybdenum-based hydrodesulfurization and dearsenization catalysts are layered into nickel-molybdenum hydrogenation reaction in a certain proportion Nitrogen heating process for Ni-Mo hydrogenation reactor, which can effectively overcome the long pre-sulfurization time, high toxicity, poor labor protection conditions and troublesome operation of the original nickel-Molybdenum hydrodesulfurization and dearsenization catalyst , And it needs to set up a vulcanizing agent generator and use a large amount of start-up circulating oil, the transportation of vulcanizing agent is difficult, it has a great corrosion effect on equipment pipelines, and the original process needs to be modified.

CN1459663A discloses a nickel sulfide nanoparticle sensitizer and its preparation method and application. The sensitizer can be used as a sensitizer of silver halide microcrystalline emulsion, or used as a silver halide microcrystalline emulsion in cooperation with water-soluble gold salt solution. The sensitizer of crystal emulsion has many advantages such as reducing latent image dispersion, improving sensitivity, improving contrast, and reducing fog.

CN1526648A discloses a wet chemical preparation method of low-dimensional nickel sulfide nanocrystals. The method uses water-in-oil microemulsion as the reaction medium, and takes inorganic nickel salt, carbon disulfide and urea as reactants, and conducts direct hydrothermal treatment in a reactor Synthesis of nickel sulfide one-dimensional nanoneedles, tubes or two-dimensional nano-thin lamellar crystals. By changing the reaction time, reactant concentration, reactant ratio and reaction medium type, or adding dodecyl mercaptan, the morphology and composition of the product can be controlled. The method has the characteristics of controllable product appearance, adjustable composition, and simple process and equipment.

CN101186346A discloses a low-temperature solid-phase synthesis method of hexagonal phase nickel sulfide submicron crystals. The method uses nickel acetate and sulfur source to react to obtain black powdery hexagonal phase nickel sulfide submicron crystals, which overcomes the existing problems in prior art methods. Harsh conditions, high energy consumption, low yield, poor purity, expensive equipment, high temperature, catalyst, highly toxic H2S gas, difficult organic solvent treatment, difficult industrialization, difficult separation of microemulsions, environmental pollution and other defects.

CN101736377A discloses a method for preparing a nickel sulfide nanowire array. The method uses porous alumina as a template, on which a zinc sulfide nanowire array is electrochemically deposited, and then the porous alumina template containing the zinc sulfide nanowire array is placed In the electrodeposition solution prepared by nickel sulfate salt and boric acid plus water, the porous alumina template containing zinc sulfide nanowire arrays is used as the cathode, and the graphite sheet is used as the anode, and DC voltage is applied at room temperature to obtain nickel sulfide-containing The porous alumina template of the nanowire array has the advantages of simple method and low cost, and is conducive to the deviceization and wide application of compound semiconductor nanostructures.

CN102605468A discloses a method for preparing nickel sulfide nanofibers, which belongs to the technical field of nanomaterial preparation. The method adopts the combination of electrospinning technology and vulcanization technology to prepare NiS nanofibers. The fibers have a good crystal form and can be As an important functional material, it is used in photocatalysis, infrared detection, solar energy storage, photosensitive materials and other fields.

CN102690657A discloses a nickel-containing fluorescent quantum dot, the quantum dot may contain nickel sulfide, which has a wide absorption spectrum and a narrow fluorescence emission spectrum, and the luminous color is adjustable with the excitation wavelength, with high luminous efficiency and good stability , can be applied to construct quantum dot solar sensitized cells and LED devices.

CN103035914A discloses a nickel sulfide flake/graphene composite material and its preparation method and application. The nickel sulfide flake/graphene composite material is composed of nanoscale nickel sulfide and graphene, wherein NiS is in the form of flakes. The nickel sulfide flakes in the composite material can be uniformly distributed and small in size due to the dispersion and loading effect of graphene, which can effectively improve the stability and cycle stability of nickel sulfide during charge and discharge, and can be used as a negative electrode material for lithium-ion batteries.

CN103474243A discloses a method for preparing a counter electrode of a dye-sensitized solar cell based on nickel sulfide nanosheets. The method includes: synthesizing a nickel xanthate precursor, preparing a counter electrode of nickel sulfide nanosheets, and photocatalyzing dye-sensitized titanium dioxide The anode and the prepared counter electrode are assembled together, and the electrolyte is injected to obtain a dye-sensitized solar cell. Compared with the traditional preparation method of the platinum-carrying conductive glass counter electrode, the preparation method of the counter electrode has the characteristics of simple process, easy control of preparation parameters, good repeatability, superior performance of materials and devices, etc., and can be mass-produced industrially.

CN103864157A discloses a preparation method of amorphous nickel sulfide, which is significantly different from the traditional preparation method of nickel sulfide: a stabilizer is added when sodium sulfide is dissolved to prevent the oxidation of sodium sulfide; to ensure the reducibility of the system, a dispersing agent to prevent the formation of polysulfides between sodium sulfides; adding a reducing agent to the copper back solution makes the system prepared by nickel sulfide appear reductive. The prepared amorphous nickel sulfide has high copper removal activity and can be used in the field of chemical purification.

CN103878031A discloses a catalyst for oil shale pyrolysis, which includes molecular sieve, activated clay, organic cobaltate, metal sulfide, glyceric acid ester and paraffin, wherein the metal sulfide can be nickel sulfide. The catalyst can improve the pyrolysis efficiency of oil shale, improve the distribution of oil shale pyrolysis products, produce more light products, and has excellent catalytic performance and catalytic efficiency.

At present, the methods for synthesizing nickel sulfide composites mainly include high-temperature synthesis, ion exchange, thermal decomposition of organic matter, electrochemical method, radiation method, and microemulsion method. However, some of these methods have harsh process conditions, some reaction processes are difficult to control, or the product yield is too low and contains a considerable amount of impurities, which all lead to the demand for new methods of synthesizing nickel sulfide.

Non-metallic elemental tellurium has excellent properties such as pyroelectricity, piezoelectricity, nonlinear optical response, photoconductivity, and catalytic activity. It is an elemental semiconductor material with a P-type narrow bandgap (direct bandgap 0.32eV).

The composite material with micro-nano structure not only has the characteristics of the original material itself, but also can play a synergistic effect between different materials, and has many unique physical and chemical properties that a single material does not have, so it has a very broad application prospect. The preparation technology of micro-nano composites has been a research hotspot in chemistry and materials in recent years.

Based on this consideration, how to combine nickel sulfide and tellurium so as to exert the synergistic effect of nickel sulfide and tellurium is the current research hotspot and focus in this field. Therefore, how to design a simple, economical and environmentally friendly method to prepare a composite material with a new nickel sulfide-tellurium nanostructure with regularity and controllable morphology is of great significance, and this is exactly what the present invention achieves foundation and motivation.

Contents of the invention

In order to overcome the many defects in the nano-nickel sulfide synthesis method pointed out above, it is necessary to seek a method for preparing a new type of nickel sulfide-tellurium nanostructure composite material with rules and controllable morphology, and to obtain the regular, shape-controllable composite material. The inventors have carried out in-depth research on a novel nickel sulfide-tellurium nanostructure composite material controlled by the inventor, and completed the present invention after paying a lot of creative work.

Specifically, the technical scheme and content of the present invention relate to a flower-shaped nickel sulfide-tellurium composite material, a preparation method and its application.

More specifically, the present invention relates to the following aspects.

In a first aspect, the present invention relates to a method for preparing a flower-shaped nickel sulfide-tellurium composite material, the method comprising the steps of:

(1) Dissolving the tellurium source precursor and the nickel source precursor in an organic solvent, then adding an organic sulfur compound and a weakly basic compound, and reacting in a closed manner under high pressure;

(2) After the reaction is finished, the pressure is released to normal pressure, and naturally cooled to room temperature, centrifuged to obtain a solid, which is washed with water and absolute ethanol in turn, and dried in vacuum to obtain the flower-shaped nickel sulfide-tellurium composite material .

In the preparation method of the present invention, the tellurium source precursor in the step (1) is an organic tellurium compound.

Wherein, the organic tellurium compound is selected from any one of tellurium diethyldithiocarbamate, biphenyl ditellurium, sodium tellurite, benzyl dibutyl tellurium bromide, and p-methoxyphenyl tellurium oxide or any mixture thereof, most preferably tellurium diethyldithiocarbamate.

In the preparation method of the present invention, the nickel source precursor in the step (1) is an organic nickel compound.

Wherein, the organic nickel compound is selected from N,N-nickel di-n-butyldithiocarbamate, nickel acetate, nickelocene, cyclododecatriene nickel, tetracarbonyl nickel, diethyl nickel, etc. Any one or a mixture of any multiple, most preferably nickel N,N-di-n-butyldithiocarbamate.

In the preparation method of the present invention, the organic solvent in the step (1) is any one or more of C _1-6 alcohol, halogenated C _1-6 alkane, heterocyclic compound, ether compound mixture of species.

Wherein, the C _1-6 alcohol refers to an alcohol with 1-6 carbon atoms, non-limiting examples may be methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, t-butyl alcohol Alcohol, n-pentanol or n-hexanol.

Wherein, the halogenated C _1-6 alkane refers to an alkane with 1-6 carbon atoms substituted by a halogen atom, for example, non-limitingly, chloroform (chloroform), methylene chloride, methylene chloride, Carbon tetrachloride, chloroethane, 1,1-dichloroethane, 1,2-dichloroethane, etc.

Wherein, the heterocyclic compound refers to a cyclic compound having a heteroatom, for example, tetrahydrofuran, pyridine, pyrimidine, morpholine, etc., without limitation.

Wherein, the ether compound may be diethyl ether, methyl ethyl ether, methyl tert-butyl ether, etc., for example.

The organic solvent is most preferably chloroform (chloroform).

In the preparation method of the present invention, the organosulfur compound in the step (1) is dithiosalicylic acid.

In the preparation method of the present invention, the weakly basic compound in the step (1) is selected from any one or any mixture of ammonia, sodium bicarbonate, sodium carbonate and the like. .

Wherein, the weakly basic compound is most preferably ammonia water, and its concentration is 25-30% in terms of the mass percentage of contained _NH3 , for example, it can be 25%, 26%, 27%, 28%, 29% or 30% %.

In the preparation method of the present invention, in the step (1), the mass ratio of the tellurium source precursor to the nickel source precursor is 1:0.5-3, non-limitingly, for example, it can be 1:0.5, 1:1, 1:1.5, 1:2, 1:2.5 or 1:3, preferably 1:1.

In the preparation method of the present invention, in the step (1), the mass volume ratio of the tellurium source precursor to the organic solvent is 1:100-300g/ml, that is, every 1g of the tellurium source precursor dissolves In 100-300ml of organic solvent, the mass-to-volume ratio of the two can be, for example, 1:100g/ml, 1:150g/ml, 1:200g/ml, 1:250g/ml or 1:300g/ml.

In the preparation method of the present invention, in the step (1), the mass ratio of the tellurium source precursor to the weakly basic compound is 1:1-3, for example, it can be 1:1, 1:2 or 1:3.

Wherein, when the weakly basic compound is ammonia water, the mass ratio of the tellurium source precursor to NH ₃ in ammonia water is 1:1-3, for example, it can be 1:1, 1:2 or 1:3.

In the preparation method of the present invention, in the step (1), the reaction pressure is 1-3 MPa, for example, 1 MPa, 2 MPa or 3 MPa.

In the preparation method of the present invention, in the step (1), the reaction temperature is 100-160°C, non-limitingly, for example, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C Or 160°C, preferably 110-150°C, more preferably 120-140°C, most preferably 130°C.

In the preparation method of the present invention, in the step (1), the reaction time is 2-6 hours, such as 2 hours, 3 hours, 4 hours, 5 hours or 6 hours, preferably 2-4 hours , most preferably 4 hours.

In the preparation method of the present invention, in the step (2), the water used for washing is deionized water, preferably high-purity water, more preferably high-purity water with an impurity content of less than 0.01 mg/L and a conductivity of less than 0.2 μs/cm .

As mentioned above, the present invention provides a method for preparing a nickel sulfide-tellurium composite material, the method does not use a template, one-step synthesis, and simple post-treatment, thereby obtaining a flower-shaped nickel sulfide-tellurium composite Material.

In the second aspect, the present invention relates to the flower-shaped nickel sulfide-tellurium composite material obtained by the above preparation method.

The flower-shaped nickel sulfide-tellurium composite material is composed of about 60% by weight of elemental tellurium and about 40% by weight of NiS, and the sum of the two is 100%.

In a third aspect, the present invention relates to the use of the flower-shaped nickel sulfide-tellurium composite material in lithium-ion batteries, that is, the use of the flower-shaped nickel sulfide-tellurium composite material in the preparation of lithium-ion batteries.

The inventors have found that the flower-shaped nickel sulfide-tellurium composite material with specific morphology obtained in the present invention can be used as the negative electrode material of lithium-ion batteries, and has good discharge capacity and cycle stability, so it can be used in the preparation of lithium-ion batteries. The battery field has great application potential and industrial value.

Description of drawings

Fig. 1 is a low magnification scanning electron microscope (SEM) image (20 μm) of the nickel sulfide-tellurium composite material M1 prepared in Example 1 of the present invention.

Fig. 2 is a high-magnification scanning electron microscope (SEM) image (2 μm) of the nickel sulfide-tellurium composite material M1 prepared in Example 1 of the present invention.

Fig. 3 is an energy spectrum (EDS) of the nickel sulfide-tellurium composite material M1 prepared in Example 1 of the present invention.

4-6 are X-ray electron spectrograms (XPS) of the nickel sulfide-tellurium composite material M1 prepared in Example 1 of the present invention.

Fig. 7 is an X-ray diffraction pattern (XRD) of the nickel sulfide-tellurium composite material M1 prepared in Example 1 of the present invention.

Fig. 8 is a high resolution transmission electron microscope image (HRTEM) (2nm) of the nickel sulfide-tellurium composite material M1 prepared in Example 1 of the present invention.

Fig. 9 is a thermogravimetric curve of the nickel sulfide-tellurium composite material M1 prepared in Example 1 of the present invention and a thermogravimetric curve of pure Te.

Figure 10 is a scanning electron microscope image (SEM) of the product obtained when the mass ratio of the tellurium source precursor to the nickel source precursor is different (both are 10 μm), wherein:

(a) is the scanning electron micrograph (SEM) of embodiment 2 nickel sulfide-tellurium composite material M2;

(b) is the scanning electron microscope image (SEM) of embodiment 1 nickel sulfide-tellurium composite material M1;

(c) is the scanning electron micrograph (SEM) of embodiment 3 nickel sulfide-tellurium composite material M3;

(d) is a scanning electron microscope image (SEM) of the nickel sulfide-tellurium composite material M4 of Example 4.

Fig. 11 is the scanning electron micrograph (SEM) of the product obtained under different reaction temperatures, wherein:

(a), (b) are the scanning electron microscope picture (SEM) of embodiment 5 nickel sulfide-tellurium composite material M5 (respectively 10 μm and 2 μm);

(c), (d) are scanning electron micrographs (SEM) of embodiment 6 nickel sulfide-tellurium composite material M6 (10 μm and 2 μm respectively);

(e), (f) are scanning electron micrographs (SEM) of embodiment 7 nickel sulfide-tellurium composite material M7 (10 μ m and 2 μ m);

(g), (h) are the scanning electron microscope (SEM) of embodiment 8 nickel sulfide-tellurium composite material M8 (respectively 10 μm and 2 μm);

(i), (j) are scanning electron micrographs (SEM) of embodiment 9 nickel sulfide-tellurium composite material M9 (10 μm and 2 μm respectively);

(k) and (l) are scanning electron microscope images (SEM) of the nickel sulfide-tellurium composite material M10 in Example 10 (10 μm and 2 μm, respectively).

Fig. 12 is the scanning electron micrograph (SEM) of nickel sulfide-tellurium composite material obtained under different reaction times, wherein:

(a), (b) are the scanning electron microscope (SEM) of embodiment 11 nickel sulfide-tellurium composite material M11 (respectively 10 μm and 1 μm);

(c), (d) are scanning electron micrographs (SEM) of embodiment 12 nickel sulfide-tellurium composite material M12 (10 μ m and 1 μ m respectively);

(e) and (f) are scanning electron microscope images (SEM) of the nickel sulfide-tellurium composite material M13 in Example 13 (10 μm and 1 μm, respectively).

13 is a graph showing the relationship between the discharge capacity and the number of cycles when the nickel sulfide-tellurium composite material M1 prepared in Example 1 of the present invention is used in a lithium-ion battery.

detailed description

The present invention will be described in detail below through specific examples, but the use and purpose of these exemplary embodiments are only used to exemplify the present invention, and do not constitute any form of any limitation to the actual protection scope of the present invention, nor will the present invention The scope of protection is limited to this.

Example 1

(1) In a stainless steel autoclave lined with polytetrafluoroethylene, dissolve tellurium diethyldithiocarbamate and nickel N,N-di-n-butyldithiocarbamate in chloroform, and then add disulfide Substitute salicylic acid, finally add ammonia water, and react in a closed manner at a pressure of 2MPa and 130°C for 4 hours. Wherein, the mass ratio of tellurium diethyldithiocarbamate to N, N-nickel di-n-butyldithiocarbamate is 1:1, and the mass-volume ratio of tellurium diethyldithiocarbamate to chloroform is 1:200g/ml, tellurium diethyldithiocarbamate and NH in aqueous ammonia _The mass ratio is 1:2;

(2) After the reaction, release the pressure to normal pressure, and naturally cool to room temperature, and centrifuge to obtain a solid, which is sequentially washed with high-purity water (the impurity content is less than 0.01mg/L, and the conductivity is less than 0.2μs/cm), without Washed with water and ethanol, and dried in a vacuum oven at 50° C. for 5 hours to obtain the flower-shaped nickel sulfide-tellurium composite material, named M1.

Example 2-4

(1) In a stainless steel autoclave lined with polytetrafluoroethylene, dissolve tellurium diethyldithiocarbamate and nickel N,N-di-n-butyldithiocarbamate in chloroform, and then add disulfide Substitute salicylic acid, finally add ammonia water, and react in a closed manner at a pressure of 2MPa and 130°C for 4 hours. Among them, the mass ratio of tellurium diethyldithiocarbamate to nickel N,N-di-n-butyldithiocarbamate is shown in Table 1 below (for simplicity, it is defined as "tellurium source precursor and nickel source The mass ratio of the precursor"), the mass volume ratio of tellurium diethyldithiocarbamate to chloroform is 1:200g/ml, the mass ratio of tellurium diethyldithiocarbamate to NH in ammonia water is ₁ :2;

(2) After the reaction, release the pressure to normal pressure, and naturally cool to room temperature, and centrifuge to obtain a solid, which is sequentially washed with high-purity water (the impurity content is less than 0.01mg/L, and the conductivity is less than 0.2μs/cm), without Wash with water and ethanol, and dry in a vacuum oven at 50° C. for 5 hours to obtain a nickel sulfide-tellurium composite material.

Table 1

Example 5-10

(1) In a stainless steel autoclave lined with polytetrafluoroethylene, dissolve tellurium diethyldithiocarbamate and nickel N,N-di-n-butyldithiocarbamate in chloroform, and then add disulfide Replace salicylic acid, add ammonia water at last, under the pressure of 2MPa and reaction temperature, airtight reaction 4 hours. Wherein, the mass ratio of tellurium diethyldithiocarbamate to N, N-nickel di-n-butyldithiocarbamate is 1:1, and the mass-volume ratio of tellurium diethyldithiocarbamate to chloroform is 1:200g/ml, tellurium diethyldithiocarbamate and the NH in aqueous _ammoniaThe mass ratio is 1:2; Described reaction temperature is shown in table 2 below;

(2) After the reaction, release the pressure to normal pressure, and naturally cool to room temperature, and centrifuge to obtain a solid, which is sequentially washed with high-purity water (the impurity content is less than 0.01mg/L, and the conductivity is less than 0.2μs/cm), without Wash with water and ethanol, and dry in a vacuum oven at 50° C. for 5 hours to obtain a nickel sulfide-tellurium composite material.

Table 2

Examples 11-13

(1) In a stainless steel autoclave lined with polytetrafluoroethylene, dissolve tellurium diethyldithiocarbamate and nickel N,N-di-n-butyldithiocarbamate in chloroform, and then add disulfide Substitute salicylic acid, add ammonia water at last, and react in airtight under 2MPa pressure and 130 ℃ for a certain period of time. Wherein, the mass ratio of tellurium diethyldithiocarbamate to N, N-nickel di-n-butyldithiocarbamate is 1:1, and the mass-volume ratio of tellurium diethyldithiocarbamate to chloroform is 1:200g/ml, tellurium diethyldithiocarbamate and the NH in aqueous ammonia _The mass ratio is 1:2; The reaction time is shown in the following table 3;

(2) After the reaction, release the pressure to normal pressure, and naturally cool to room temperature, and centrifuge to obtain a solid, which is sequentially washed with high-purity water (the impurity content is less than 0.01mg/L, and the conductivity is less than 0.2μs/cm), without Wash with water and ethanol, and dry in a vacuum oven at 50° C. for 5 hours to obtain a nickel sulfide-tellurium composite material.

table 3

Microscopic representation

The nickel sulfide-tellurium composite material obtained in Example 1 has been microscopically characterized by a number of different means, and the results are as follows:

1. As can be seen from the scanning electron microscope (SEM) images of Figures 1-2, the nickel sulfide-tellurium composite material is in the shape of a micron-scale flower with uniform and controllable morphology.

2. The energy spectrum (EDS) test in Figure 3 shows that the sample contains three elements: Ni, S, and Te, indicating that the prepared flower-shaped composite material contains three elements: Te, S, and Cd (Cu is caused by the copper mesh, C is caused by the carbon film on the copper mesh).

3. From the X-ray photoelectron spectroscopy (XPS) in Figure 4-6, it can be seen that in the flower-shaped nickel sulfide-tellurium composite material, Te exists in a zero valence state, Ni exists in a +2 valence state, and S exists in a +2 valence state. The existence of -2 valence indicates that the composite material is composed of elemental tellurium and nickel sulfide.

4. From the X-ray diffraction pattern (XRD) in Figure 7, it can be seen that only the diffraction peaks of hexagonal tellurium appear in the figure, but there are no diffraction peaks of S and Ni. This shows that the flower-like composite contains elemental tellurium in the hexagonal phase.

5. From the high-resolution transmission electron microscope image (HRTEM) in Figure 8, it can be seen that the spacing is 0.223nm, which is consistent with the (110) crystal plane spacing of the hexagonal tellurium phase, indicating that its growth direction is parallel to the (110) crystal plane face growing.

6. It can be seen from the thermogravimetric curve in Fig. 9 that graphs a and b are the TG graph of the prepared flower-like composite and the TG graph of pure tellurium, respectively. Since γ-NiS transforms into β-NiS at 396°C, and the melting point of β-NiS is 810°C, the TG diagrams of the flower-shaped composite material of the present invention containing tellurium and pure tellurium are different in the first 600°C, but the general trend same. When the temperature was raised to 1000°C, almost no pure tellurium product remained, while 40% of the flower-like complex eventually remained. Therefore, it can be known that the weight content of tellurium in the flower-shaped composite material is about 60%. It can be concluded that the flower-shaped composite material in Example 1 of the present invention is composed of about 60% by weight of elemental tellurium and about 40% by weight of NiS.

7. As can be seen from Examples 2-4 and Figure 10, when the nickel source precursor is not added, the flower-shaped product cannot be obtained at all (see figure (a)), and when the tellurium source precursor and the nickel source precursor When the mass ratio is higher than 1:1 (such as 1:2 or 1:3, see Figures (c) and (d)), the obtained product is flower-like, but the size is not uniform, and there are some fragments. Shangyuan is not more uniform and regular than when it is 1:1, which proves that the mass ratio of the two is 1:1 to have the best effect.

8. It can be seen from Examples 5-10 and Figure 11 that the temperature has a significant impact on the shape of the final composite material, and a uniform and regular flower-shaped composite material can be produced at 120-140 ° C, while outside this range, The resulting product is significantly reduced in regularity and uniformity.

9. It can be seen from Examples 11-13 and Figure 12 that the reaction time has a significant impact on the morphology of the final composite material. When the time is less than 2 hours, the flower-shaped composite material cannot be obtained, and when the temperature is 4 hours, The flower-like composite material with the most uniform and regular shape can be obtained.

In summary, it can be seen from all the above-mentioned embodiments that the preparation method of the present invention is very simple, and the flower-shaped nickel sulfide-tellurium composite material with unique morphology can be prepared only by one-step hydrothermal reaction, which is effective Problems such as agglomeration of nickel sulfide are prevented, and the morphology of the prepared nickel sulfide-tellurium composite material is regular and controllable, and the reaction conditions are mild and the post-treatment is simple.

At the same time, the inventors found that the flower-shaped nickel sulfide-tellurium composite material of the present invention can be used as the negative electrode material of lithium-ion batteries, has excellent initial discharge capacity and cycle stability, and thus can be applied in the field of lithium-ion batteries.

Lithium-ion battery performance test

The flower-shaped nickel sulfide-tellurium composite material gained in Example 1 is used for lithium-ion batteries, and the specific processing method is:

After mixing the composite material of Example 1, carbon black, and polytetrafluoroethylene (PTFE) uniformly according to the mass ratio of 8:1:1, apply it on the surface of copper foil with a width of 10mm, and dry it at 100°C for at least 8h under vacuum conditions, that is, Working electrode is available. Lithium metal was used as the counter electrode, and LiPF ₆ was dissolved in a mixture of ethylene carbonate (EC), dimethyl carbonate (DMC) and diethyl carbonate (DEC) (volume ratio 1:1:1) as the electrolyte. , the molar concentration of LiPF ₆ was 1 mol/L, and the battery assembly was performed in an argon-protected glove box.

The electrochemical performance test adopts a two-electrode system, and the cycle performance is tested on a charge-discharge test system (LandCT2001). The corresponding charge-discharge current density is 0.2mA/cm ² , and the potential range is 3.0-0.1V.

When the samples used are the flower-shaped nickel sulfide-tellurium composite material prepared in Example 1 of the present invention and the non-tellurium cadmium sulfide, the discharge capacity and cycle stability are shown in Figure 13. It can be seen from the accompanying drawing that the initial discharge capacity of the flower-shaped nickel sulfide-tellurium composite material of the present invention exceeds 1200mA h/g, and after 30 cycles, the discharge capacity can still be maintained at about 420mA h/g, without cadmium tellurium sulfide The first discharge capacity is only about 980mA h/g, and it is 260mA h/g after 30 cycles, which proves that the flower-like cadmium sulfide-tellurium composite material of the present invention has excellent cycle stability and can be used as a lithium ion The negative electrode material of the battery can be used in the field of lithium-ion batteries.

It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the protection scope of the present invention. In addition, it should also be understood that after reading the technical content of the present invention, those skilled in the art can make various changes, modifications and/or variations to the present invention, and all these equivalent forms also fall within the appended claims of the present application. within the defined scope of protection.

Claims (10)

1. a preparation method of flower-shaped nickel sulfide-tellurium composite material, said method may further comprise the steps: (1) Dissolving the tellurium source precursor and the nickel source precursor in an organic solvent, then adding an organic sulfur compound and a weakly basic compound, and reacting in a closed manner under a reaction pressure of 1-3 MPa; (2) After the reaction is finished, the pressure is released to normal pressure, and naturally cooled to room temperature, centrifuged to obtain a solid, which is washed with water and absolute ethanol in turn, and vacuum-dried to obtain the flower-shaped nickel sulfide-tellurium composite material ; The organosulfur compound in the step (1) is dithiosalicylic acid; The mass ratio of the tellurium source precursor to the nickel source precursor is 1:1; In the step (1), the reaction temperature is 120-140°C; the reaction time is 2-4 hours. 2. The preparation method according to claim 1, wherein the tellurium source precursor is selected from tellurium diethyldithiocarbamate, biphenyl ditellurium, sodium tellurite, benzyl dibutyl bromide Any one or any mixture of tellurium base tellurium, p-methoxyphenyl tellurium oxide. 3. The preparation method according to claim 2, characterized in that: the tellurium source precursor is tellurium diethyldithiocarbamate. 4. The preparation method according to claim 1 or 2, characterized in that: the nickel source precursor is selected from the group consisting of N,N-di-n-butyl dithiocarbamate nickel, nickel acetate, nickelocene, cyclodeca Any one or a mixture of any of nickel dicarbatriene, nickel tetracarbonyl, and diethyl nickel. 5. The preparation method according to claim 1, characterized in that: the nickel source precursor is nickel N,N-di-n-butyldithiocarbamate. 6. The preparation method according to any one of claims 1-3, characterized in that: the weakly basic compound in the step (1) is selected from any one or any of ammonia, sodium bicarbonate, sodium carbonate Various mixtures. 7. The preparation method according to any one of claims 1-3, characterized in that: in the step (1), the mass ratio of the tellurium source precursor to the weakly basic compound is 1:1-3. 8. The preparation method according to any one of claims 1-3, characterized in that: in the step (1), the reaction temperature is 130° C.; the reaction time is 4 hours. 9. The flower-shaped nickel sulfide-tellurium composite material obtained by the preparation method described in any one of claims 1-8. 10. the purposes of claim 9 said flower-shaped nickel sulfide-tellurium composite material in lithium ion battery.