A hollow Cu 3 Mo 2 O 9 micron sphere and its preparation method and application

Abstract

The present invention discloses a hollow Cu3Mo2O9 microsphere and its preparation method and application. Using copper nitrate and molybdenum acetylacetonate as reaction materials and glycerol as a surfactant, the Cu3Mo2O9 microsphere material is prepared by a solvothermal method and a heat treatment process. This preparation method has the advantages of simple process, low cost, good repeatability and high product purity. When used as the anode of a lithium-ion battery, the Cu3Mo2O9 microsphere exhibits an extremely high lithium storage specific capacity and excellent cycle stability. At a current density of 0.1 A / g, the initial discharge specific capacity is as high as 1002.7 mA h / g, and its capacity still remains at about 850 mA h / g after 100 cycles.

Description

Technical Field

[0001] The present invention belongs to the technical field of micro-nano synthesis and lithium-ion battery energy storage, and particularly relates to a hollow Cu3Mo2O9 microsphere and a preparation method and application thereof. Background Art

[0002] Currently, the present invention belongs to the technical field of preparation and energy storage of nano-micro materials, and particularly relates to a preparation method and application of a copper-based molybdate nano-micro material. Lithium-ion batteries have the advantages of high energy density, light weight, long cycle life, etc., and have been widely used in fields such as portable electronic products, power tools, and electric vehicles. As a key component of lithium-ion batteries, the performance of the negative electrode material directly determines the performance of lithium-ion batteries. In the past few decades, people have been committed to synthesizing negative electrode materials with unique structures to improve their energy density and safety. In the field of inorganic functional materials, molybdates are important energy storage materials due to their low cost, high theoretical capacity, rich valence states, high conductivity, and high natural abundance. Therefore, they are widely used in many cutting-edge fields.

[0003] Cu 3 Mo 2 O 9 is one of the typical representatives in molybdates. Cu 3 Mo 2 O 9 has excellent charge and discharge stability and extremely high Coulomb efficiency, and has great potential in the application of electrode materials. Currently, the main preparation methods include solid-phase sintering, ultrasonic calcination method, etc. There is a method of synthesizing uniformly distributed Cu 3 Mo 2 O 9 inorganic nano-semiconductor materials on a copper mesh by using simple anodic oxidation and high-temperature calcination method. There is also a method of synthesizing a Cu 3 Mo 2 O 9 nano-sheet array material by using ultrasonic calcination method with low-cost copper source and molybdenum source as reaction raw materials. The above reports prove that different micron-structured Cu 3 Mo 2 O 9 have wide applications in various research fields, but due to the disadvantage that Cu 3 Mo 2 O 9 materials are prone to agglomeration, their rate and cycle performance in the field of battery energy storage do not reach the ideal level. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a hollow Cu3Mo2O9 microsphere, its preparation method and application in view of the deficiencies in the above-mentioned prior art. A novel Cu 3 Mo 2 O 9 microsphere structure is prepared by a glycerol-assisted solvothermal method and subsequent simple heat treatment to solve the technical problems of easy agglomeration of Cu 3 Mo 2 O 9 materials and poor long-cycle performance in the field of battery energy storage.

[0005] The present invention adopts the following technical solutions:

[0006] A preparation method of hollow Cu3Mo2O9 microspheres uses glycerol as a surfactant and dissolves it in isopropanol to obtain a mixed solution A. Then, copper nitrate and molybdenum acetylacetonate are used as reaction materials and added to the mixed solution A to obtain solution B. Based on solution B, Cu 3 Mo 2 O 9 microspheres are prepared by a solvothermal method and a heat treatment process.

[0007] Specifically, in the mixed solution A, the volume ratio of glycerol to isopropanol is 1:(6-8).

[0008] Specifically, copper nitrate and molybdenum acetylacetonate are added to the mixed solution A and magnetically stirred at room temperature for 4-8 hours until completely dissolved to obtain solution B.

[0009] Furthermore, the molar ratio of copper nitrate to molybdenum acetylacetonate is 3:2, and the mass ratio of copper nitrate and molybdenum acetylacetonate to the mixed solution A is (3-5):1.

[0010] Specifically, solution B is placed in a high-pressure reaction kettle, and the product C is obtained by heating and pressurizing the reaction in an oven; then the product C is centrifuged and washed repeatedly with ethanol, and then dried to obtain CuMo-glycerol precursor microspheres. The synthesized CuMo-glycerol microspheres are placed in an air furnace for reaction. After the reaction is completed, they are cooled to room temperature to obtain Cu 3 Mo 2 O 9 microspheres.

[0011] Furthermore, the solvothermal temperature of the heating and pressurizing reaction is 150-200 °C, and the reaction time is 8-24 h.

[0012] Furthermore, the number of washing times is 2-5 times.

[0013] Furthermore, the reaction temperature of the air furnace is set at 500-700 °C and the heating rate is 5 °C / min, and the reaction time is 2-3 hours.

[0014] The second technical solution of the present invention is a hollow Cu 3 Mo 2 O 9 micron sphere.

[0015] The third technical solution of the present invention is that the hollow Cu3Mo2O9 micron sphere is applied to the negative electrode of a lithium-ion battery.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects:

[0017] A method for preparing a hollow Cu3Mo2O9 micron sphere, using copper nitrate and molybdenum acetylacetonate as reaction materials and glycerol as a surfactant, and preparing a Cu 3 Mo 2 O 9 micron sphere material by a solvothermal method and a heat treatment process. This preparation method has a simple process, low cost, good repeatability, and high product purity.

[0018] Furthermore, the volume ratio of glycerol to isopropyl alcohol is set to 1:(6 - 8) because isopropyl alcohol can dissolve metal salts well, and the large hydrogen bonds in glycerol are conducive to forming metal chelates with metal ions. Setting the volume ratio in this way can not only make the compatibility better but also effectively control the nucleation and growth of metal ions.

[0019] Furthermore, magnetic stirring is carried out at room temperature for 4 - 8 hours until completely dissolved to obtain solution B. The purpose is to allow the solute to fully diffuse into the solvent, enabling the metal salt and glycerol to fully blend, thereby reducing the surface energy and forming a homogeneous solution.

[0020] Furthermore, the molar ratio of copper nitrate to molybdenum acetylacetonate is 3:2 to have an equal molar mass between the solution and the solute to achieve the best effect; and this molar ratio corresponds to the formation of a Cu 3 Mo 2 O 9 new material. Other ratios may generate impurities such as copper oxide or molybdenum oxide. The mass ratio of the mixed solution A is 5:1 - 3:1 because the solution concentration has a very important influence on the crystal growth and material morphology during the solvothermal high-temperature and high-pressure process. The appropriate concentration is the key to generating the target product and morphology of this solution.

[0021] Furthermore, solution B is heated and pressurized in a high-pressure reaction kettle to obtain a CuMo-glycerol precursor micron sphere because this solvothermal method can complete the smooth buffering of the fluid pressure of the medium and the gas purification and separation equipment in the high-pressure reaction kettle, and it is conducive to the controllable synthesis of materials and the ordered growth of crystals under high temperature and high pressure.

[0022] Furthermore, the solvothermal temperature of the temperature-raising and pressure-raising reaction is 150-200 °C, and the reaction time is 8-24 h. This is because the autoclave uses a precise control system that can accurately control factors such as the concentration, pressure, and temperature of the medium during the reaction, thus enabling a controllable reaction. The growth of crystals is usually determined by temperature and time. When a certain temperature is reached, the crystals begin to grow and continuously nucleate and grow with time. However, if the temperature is too high, the reaction may become uncontrollable and the crystal growth may be irregular.

[0023] Furthermore, the purpose of setting the number of centrifugal washing times is to remove the soluble impurities on the crystal surface to obtain purer crystals, wash the residue obtained by washing and filtering, and wash out as much useful substances, such as the target product, as possible to obtain a pure target product.

[0024] Furthermore, the reaction temperature in the air furnace is set to 500-700 °C because calcination at high temperature can cause better decomposition of copper nitrate and molybdenum acetylacetonate and then react to obtain Cu 3 Mo 2 O 9 micron spheres; as the reaction temperature increases, due to the Kirkendall effect, the micron sphere structure gradually grows from solid micron spheres to hollow micron spheres; if the temperature is too high, the sphere structure will be damaged and become an irregular structure.

[0025] In summary, the preparation method of the present invention has the advantages of simple process, low cost, good repeatability, and high product purity.

[0026] Next, through the drawings and examples, the technical solutions of the present invention will be further described in detail. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is the XRD pattern of Cu 3 Mo 2 O 9 micron spheres;

[0028] Figure 2 is the SEM image of Cu 3 Mo 2 O 9 micron spheres;

[0029] Figure 3 is the battery cycle performance graph when Cu 3 Mo 2 O 9 micron spheres are used as the battery negative electrode. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The technical solution of the present invention will be described clearly and completely below. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0031] In the present invention, if there is no special explanation, all the embodiments and preferred implementation methods mentioned herein can be combined with each other to form a new technical solution.

[0032] In the present invention, if there is no special explanation, all the technical features and preferred features mentioned herein can be combined with each other to form a new technical solution.

[0033] In the present invention, if there is no special explanation, the percentage (%) or part refers to the weight percentage or weight part relative to the composition.

[0034] In the present invention, if there is no special explanation, the various components or their preferred components involved can be combined with each other to form a new technical solution.

[0035] In the present invention, unless otherwise stated, the numerical range "a~b" represents an abbreviated representation of any real number combination between a and b, where both a and b are real numbers. For example, the numerical range "6~22" means that all real numbers between "6~22" have been fully listed herein, and "6~22" is only an abbreviated representation of these numerical combinations.

[0036] The "range" disclosed in the present invention can be in the form of one or more lower limits and one or more upper limits respectively.

[0037] In the present invention, the term "and / or" used herein refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0038] In the present invention, unless otherwise stated, each reaction or operation step can be carried out in sequence or in order. Preferably, the reaction methods herein are carried out in sequence.

[0039] Unless otherwise stated, the professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art. In addition, any method or material similar or equivalent to the recorded content can also be applied to the present invention.

[0040] The present invention provides a hollow Cu 3 Mo 2 O 9Micron spheres and their preparation methods and applications. Using copper nitrate and molybdenum acetylacetonate as reaction materials and glycerol as a surfactant, Cu 3 Mo 2 O 9 micron sphere materials are prepared by a solvothermal method and a heat treatment process. When the Cu 3 Mo 2 O 9 micron spheres prepared by the method of the present invention are used as the anode of a lithium-ion battery, they exhibit extremely high lithium storage specific capacity and excellent cycle stability. At a current density of 0.1 A / g, the initial discharge specific capacity is as high as 1002.7 mAh / g, and after 100 cycles, the capacity still remains at about 850 mAh / g.

[0041] Please refer to Figure 1 , a method for preparing a hollow Cu 3 Mo 2 O 9 micron sphere of the present invention includes the following steps:

[0042] S1. Dissolve glycerol in isopropanol to obtain a mixed solution A;

[0043] In the mixed solution A, the volume ratio of glycerol to isopropanol is 1:(6 - 8).

[0044] S2. Weigh 0.3 mmol of copper nitrate and 0.2 mmol of molybdenum acetylacetonate, add them to the mixed solution A obtained in step S1, and place them on a magnetic stirrer to stir at room temperature for 4 - 8 hours until completely dissolved to obtain a solution B;

[0045] The molar ratio of copper nitrate to molybdenum acetylacetonate is 3:2, and the mass ratio of copper nitrate and molybdenum acetylacetonate to the mixed solution A is (3 - 5):1.

[0046] S3. Put the solution B obtained in step S2 into a 50 mL autoclave, tighten it, and then heat and pressurize it in an oven. Set the solvothermal temperature to 150 - 200 °C and the reaction time to 8 - 24 h, and observe the morphological changes and growth rules of the product;

[0047] S4. After the reaction in step S3 is completed, centrifuge and wash the product with ethanol repeatedly for 2 - 5 times, then put the sample into an oven to dry. When the sample is dry, CuMo-glycerol precursor micron spheres are obtained;

[0048] S5. Put the synthesized CuMo-glycerol micron spheres into an air furnace, and react for 2 - 3 hours under the conditions of a reaction temperature of 500 - 700 °C and a heating rate of 5 °C / min; after the reaction is completed and cooled to room temperature, the collected sample is the Cu 3 Mo 2 O 9 micron spheres.

[0049] The hollow Cu 3 Mo 2 O 9 micron spheres prepared by the method of the present invention are applied to the anode material of lithium-ion batteries, showing extremely high specific lithium storage capacity and excellent cycle stability. At a current density of 0.1 A / g, the initial discharge specific capacity is as high as 1002.7 mAh / g, and its capacity still remains at about 850 mA h / g after 100 cycles.

[0050] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components described and shown in the accompanying drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0051] Example 1

[0052] By mass, copper nitrate and molybdenum acetylacetonate with a molar ratio of 3:2 are dissolved in a mixed solution A containing isopropyl alcohol and glycerol to obtain a mixed solution B. The volume ratio of glycerol to isopropyl alcohol in the mixed solution A is 1:6, and the mass ratio of copper nitrate and molybdenum acetylacetonate to the mixed solution A is 5:1;

[0053] After stirring solution A until it is completely uniform, it is placed in a high-pressure reaction kettle, tightened, and then heated and pressurized in an oven. The reaction temperature is set at 150 °C and the reaction time is 6 hours;

[0054] After completely cooling naturally, the product formed by the reaction is centrifuged and washed repeatedly with ethanol, and then placed in an oven to dry until the sample is dry, thus obtaining CuMo-glycerol precursor micron spheres;

[0055] Finally, the obtained CuMo-glycerol micron spheres are placed in a muffle furnace and sintered for 2 hours at a reaction temperature of 500 °C and a rate of 5 °C / min;

[0056] After the reaction is completed, the collected sample is Cu 3 Mo 2 O 9 micron spheres.

[0057] Example 2

[0058] By mass fraction, copper nitrate and molybdenum acetylacetonate with a molar ratio of 3:2 are dissolved in a mixed solution A containing isopropanol and glycerol to obtain a mixed solution B. The volume ratio of glycerol to isopropanol in the mixed solution A is 1:6, and the mass ratio of copper nitrate and molybdenum acetylacetonate to the mixed solution A is 5:1;

[0059] After stirring solution A until it is completely homogeneous, it is placed in a high-pressure reactor. After tightening, the temperature and pressure are increased in an oven. The reaction temperature is set at 170 °C and the reaction time is 12 hours;

[0060] After complete natural cooling, the product formed by the reaction is centrifuged and washed repeatedly with ethanol, and then placed in an oven to dry until the sample is dry, thus obtaining CuMo-glycerol precursor microspheres;

[0061] Finally, the obtained CuMo-glycerol microspheres are placed in a muffle furnace and sintered for 2 hours under the conditions of a reaction temperature of 550 °C and a rate of 5 °C / min;

[0062] After the reaction is completed, the collected sample is Cu 3 Mo 2 O 9 microspheres.

[0063] Example 3

[0064] By mass fraction, copper nitrate and molybdenum acetylacetonate with a molar ratio of 3:2 are dissolved in a mixed solution A containing isopropanol and glycerol to obtain a mixed solution B. The volume ratio of glycerol to isopropanol in the mixed solution A is 1:8, and the mass ratio of copper nitrate and molybdenum acetylacetonate to the mixed solution A is 3:1;

[0065] After stirring solution A until it is completely homogeneous, it is placed in a high-pressure reactor. After tightening, the temperature and pressure are increased in an oven. The reaction temperature is set at 190 °C and the reaction time is 20 hours;

[0066] After complete natural cooling, the product formed by the reaction is centrifuged and washed repeatedly with ethanol, and then placed in an oven to dry until the sample is dry, thus obtaining CuMo-glycerol precursor microspheres;

[0067] Finally, the obtained CuMo-glycerol microspheres are placed in a muffle furnace and sintered for 3 hours under the conditions of a reaction temperature of 600 °C and a rate of 5 °C / min;

[0068] After the reaction is completed, the collected sample is Cu 3 Mo 2 O 9 microspheres.

[0069] Example 4

[0070] By mass fraction, copper nitrate and molybdenum acetylacetonate with a molar ratio of 3:2:3 are dissolved in a mixed solution A containing isopropanol and glycerol to obtain a mixed solution B. The volume ratio of glycerol to isopropanol in the mixed solution A is 1:8, and the mass ratio of copper nitrate and molybdenum acetylacetonate to the mixed solution A is 3:1.

[0071] After stirring solution A until it is completely homogeneous, it is placed in a high-pressure reactor. After tightening, it is heated and pressurized in an oven. The reaction temperature is set at 200 °C, and the reaction time is 24 hours.

[0072] After complete natural cooling, the product formed by the reaction is centrifuged and washed repeatedly with ethanol, and then placed in an oven to dry until the sample is dry, thus obtaining CuMo-glycerol precursor microspheres.

[0073] Finally, the obtained CuMo-glycerol microspheres are placed in a muffle furnace and sintered for 3 hours under the conditions of a reaction temperature of 700 °C and a rate of 5 °C / min.

[0074] After the reaction is completed, the collected sample is Cu 3 Mo 2 O 9 microspheres.

[0075] Please refer to Figure 1 , which is the XRD pattern of the synthesized product. It can be determined from Figure 1 that the synthesized product is Cu 3 Mo 2 O 9 , and it has a high purity.

[0076] Please refer to Figure 2 , which is the scanning electron microscope image of the synthesized product. It can be seen that the morphology of the synthesized Cu 3 Mo 2 O 9 material is distinct, presenting an obvious hollow microsphere structure.

[0077] Please refer to Figure 3 , which is the cyclic performance graph of the synthesized product as the battery anode. It can be seen that at a current density of 0.1 A / g, the Cu 3 Mo 2 O 9 anode shows excellent cyclic performance, and its capacity still remains at about 850 mAh / g after 100 cycles.

[0078] In summary, for a hollow Cu3Mo2O9 microsphere, its preparation method and application in the present invention, a hollow Cu 3 Mo 2 O 9The microsphere structure exhibits extremely high specific lithium storage capacity and excellent cycle stability, and has broad application prospects in the fields of new energy and energy storage, etc.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing hollow Cu3Mo2O9 microspheres, characterized in that, Using glycerol as a surfactant, dissolve it in isopropyl alcohol to obtain a mixed solution A. Then, use copper nitrate and molybdenum acetylacetonate as reaction materials and add them to the mixed solution A. Under room temperature conditions, stir magnetically for 4 to 8 hours until completely dissolved to obtain solution B. The molar ratio of copper nitrate to molybdenum acetylacetonate is 3:2, and the mass ratio of copper nitrate and molybdenum acetylacetonate to the mixed solution A is (3 to 5):

1. Place solution B in a high-pressure reactor and carry out a solvent thermal reaction in an oven to obtain product C. The solvent thermal temperature of the temperature and pressure increase reaction is 150 to 200 °C, and the reaction time is 8 to 24 h. Then, repeatedly centrifuge and wash product C with ethanol for 2 to 5 times, and then perform a drying treatment. After drying, a CuMo-glycerol precursor microsphere is obtained. Put the synthesized CuMo-glycerol microsphere into an air furnace for reaction. Set the reaction temperature of the air furnace to 500 to 700 °C and the heating rate to 5 °C / min. The reaction time is 2 to 3 hours. After the reaction is completed, cool it to room temperature to prepare Cu 3 Mo 2 O 9 microspheres.

2. The method for preparing hollow Cu3Mo2O9 microspheres according to claim 1, characterized in that, In the mixed solution A, the volume ratio of glycerol to isopropanol is 1:(6-8).

3. The hollow Cu3Mo2O9 microspheres prepared by the method for preparing hollow Cu3Mo2O9 microspheres according to claim 1 or 2 3 Mo 2 O 9 microspheres.

4. The hollow Cu3Mo2O9 microspheres according to claim 3 are applied to the negative electrode of a lithium ion battery.

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