阅读说明：本技术 一种ZnMoO4电活性材料、制备方法及应用 (ZnMoO4Electroactive material, preparation method and application ) 是由 林健健 许慧忠 郑德华 周倩男 孙蕾 耿佳辉 程朝阳 于 2020-12-04 设计创作，主要内容包括：本发明属于锂离子电池电极材料技术领域,公开了一种ZnMoO-4电活性材料、制备方法及应用,包括：将六水合硝酸锌、二水合钼酸钠、氟化铵和尿素按一定比例称量后超声溶解于混合溶剂中,得到混合溶液；将得到的混合溶液转移至不锈钢高压反应釜中,将反应釜放入烘箱中加热,保温一段时间；待反应釜冷却至室温后,离心得到白色沉淀物,分别用无水乙醇和去离子水超声分散离心洗涤,干燥后收集白色粉末；将收集的白色粉末转移至管式炉中,在氩气氛围中进行退火处理,冷却至室温即可得ZnMoO-4电活性材料。本发明所需原料成本低、制备方法简单、易于操作、重复性好,本发明制备得到的ZnMoO-4材料具有较高的结晶性和纯度。(The invention belongs to the technical field of lithium ion battery electrode materials, and discloses ZnMoO 4 An electroactive material, a method of making and use comprising: weighing zinc nitrate hexahydrate, sodium molybdate dihydrate, ammonium fluoride and urea according to a certain proportion, and ultrasonically dissolving in a mixed solvent to obtain a mixed solution; transferring the obtained mixed solution into a stainless steel high-pressure reaction kettle, putting the reaction kettle into an oven for heating, and preserving heat for a period of time; after the reaction kettle is cooled to room temperature, centrifuging to obtain a white precipitate, performing ultrasonic dispersion and centrifugal washing respectively by using absolute ethyl alcohol and deionized water, and collecting white powder after drying; transferring the collected white powder to a tube furnace, and annealing in argon atmosphereCooling to room temperature to obtain ZnMoO 4 An electroactive material. The ZnMoO prepared by the invention has the advantages of low cost of required raw materials, simple preparation method, easy operation and good repeatability 4 The material has high crystallinity and purity.)

1. ZnMoO₄A method for preparing an electroactive material, characterized in that the ZnMoO is used as a catalyst₄The preparation method of the electroactive material comprises the following steps:

weighing zinc nitrate hexahydrate, sodium molybdate dihydrate, ammonium fluoride and urea according to a certain proportion, and ultrasonically dissolving in a mixed solvent to obtain a mixed solution;

transferring the obtained mixed solution into a stainless steel high-pressure reaction kettle, putting the reaction kettle into an oven for heating, and preserving heat;

after the reaction kettle is cooled to room temperature, centrifuging to obtain a white precipitate, performing ultrasonic dispersion and centrifugal washing respectively by using absolute ethyl alcohol and deionized water, and collecting white powder after drying;

transferring the collected white powder to a tube furnace, annealing in argon atmosphere, and cooling to room temperature to obtain ZnMoO₄An electroactive material.

2. The ZnMoO of claim 1, wherein₄The preparation method of the electroactive material is characterized in that the molar ratio of zinc nitrate hexahydrate, sodium molybdate dihydrate, ammonium fluoride and urea is a: b: c: d, wherein a is more than or equal to 0 and less than or equal to 2; b is more than or equal to 0 and less than or equal to 2; c is more than or equal to 0 and less than or equal to 4; d is more than or equal to 0 and less than or equal to 5.

3. The ZnMoO of claim 1, wherein₄The preparation method of the electroactive material is characterized in that the mixed solvent is formed by mixing deionized water and ethanol according to a certain proportion.

4. The ZnMoO of claim 3, wherein₄The preparation method of the electroactive material is characterized in that the volume ratio of deionized water to ethanol in the mixed solvent is x: y, wherein x is more than or equal to 1 and less than or equal to 3; y is more than or equal to 0 and less than or equal to 2.

5. The ZnMoO of claim 1, wherein₄The preparation method of the electroactive material is characterized in that the reaction kettle is placed in an oven to be heated, and the heat preservation comprises the following steps: and (3) putting the reaction kettle into an oven to be heated at 160 ℃, and preserving heat for 10-12 h.

6. The ZnMoO of claim 1, wherein₄The preparation method of the electroactive material is characterized in that the ultrasonic dispersion centrifugal washing by respectively using absolute ethyl alcohol and deionized water comprises the following steps: and (3) ultrasonically dispersing and centrifugally washing the white precipitate for 3-5 times by respectively using absolute ethyl alcohol and water.

7. The ZnMoO of claim 1, wherein₄A method of preparing an electroactive material, wherein the centrifuging comprises: the centrifugal speed is 5000-8500 r/min, and the centrifugal time is 6-10 min.

8. The ZnMoO of claim 1, wherein₄A method of making an electroactive material, wherein the annealing comprises: the heating rate is 1-5 ℃/min, the annealing temperature is 400-450 ℃, and the constant temperature time is 2-4 h.

9. Use of the ZnMoO of any of claims 1 to 8₄ZnMoO prepared by preparation method of electroactive material₄An electroactive material.

10. The ZnMoO of claim 9₄The electroactive material is used as a negative electrode material of a lithium ion battery.

Technical Field

The invention belongs to the technical field of lithium ion battery electrode materials, and particularly relates to ZnMoO₄An electroactive material, a preparation method and an application.

Background

At present, with the rapid development of global economy, the increasing consumption of fossil fuels and the environmental pollution caused by the fossil fuels, people urgently need novel renewable energy sources with high efficiency and cleanness. New renewable energy sources such as solar energy, wind energy, geothermal energy and the like gradually become mainstream of energy consumption. However, new energy sources such as wind energy, geothermal energy, etc. have the characteristics of intermittence and dispersion, and are influenced by natural factors such as seasons, regional conditions, etc., and in order to effectively utilize the energy sources, corresponding electrochemical energy storage equipment is urgently needed to store the energy sources. Among various electrochemical energy storage devices, lithium ion batteries have received wide attention all over the world due to their advantages of high energy conversion efficiency, stable cycle, simple maintenance, strong power/energy adaptability, and the like.

Graphite materials are low in cost, have excellent physical and chemical stability, and have acceptable cycle-chargeability, and are widely used as negative electrode materials for commercial lithium ion batteries. However, the graphite material has a lower theoretical capacity (372mAh g)^-1) And lithium ion intercalation/deintercalation rate, greatly limiting its practical application. Therefore, in the face of increasing demand for high-performance lithium ion batteries, development of a novel high-performance lithium ion battery negative electrode material is urgently needed. As a transition metal oxide, ZnMoO₄Has relatively high specific charge-discharge capacity (951.6mAh g)^-1) Moreover, the price is low, the synthesis method is simple, and the method is favored by the wide researchers。

The analysis shows that the commercial lithium ion graphite negative electrode material has relatively low specific capacity and poor dynamics, and is difficult to meet the requirements of the current society on high-energy and high-power energy storage materials, so that a commercial replaceable lithium ion battery negative electrode material is urgently needed to be found. Therefore, the development of a novel lithium ion battery cathode material and the search of an energy storage mechanism of the lithium ion battery cathode material have important scientific significance.

Through the above analysis, the problems and defects of the prior art are as follows: the conventional lithium ion battery cathode material has low theoretical capacity and low lithium ion intercalation/deintercalation rate; ZnMoO is not available in the prior art₄The technology is applied to the negative electrode material of the lithium ion battery.

The difficulty in solving the above problems and defects is: ZnMoO₄Morphology control of electroactive materials, typically ZnMoO prepared₄Electroactive materials are typically large, blocky structures that are not conducive to contacting the electrodes with the electrolyte solution and that consume large amounts of electrolyte solution to form a solid electrolyte interface film. The lithium ion intercalation/deintercalation rate problem, and ZnMoO control₄Forming nano sheet material to shorten the diffusion path of lithium ion.

The significance of solving the problems and the defects is as follows: ZnMoO obtained by the invention₄The electroactive material has an obvious lamellar structure, so that the effective specific surface area of the material and the utilization rate of the active material are increased; ZnMoO₄The gaps among the nanosheets shorten the diffusion path of lithium ions, and are beneficial to the insertion and extraction of the lithium ions, so that the electrochemical performance of the electrode material is improved. Provides a new scheme for developing a novel lithium ion battery cathode material.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides ZnMoO₄An electroactive material, a preparation method and an application.

The invention is realized in the way that ZnMoO₄Method for preparing an electroactive material, said ZnMoO₄The preparation method of the electroactive material comprises the following steps:

step one, weighing zinc nitrate hexahydrate, sodium molybdate dihydrate, ammonium fluoride and urea according to a certain proportion, and ultrasonically dissolving in a mixed solvent to obtain a mixed solution;

transferring the obtained mixed solution into a stainless steel high-pressure reaction kettle, putting the reaction kettle into an oven for heating, and preserving heat for a period of time;

step three, after the reaction kettle is cooled to room temperature, centrifuging to obtain a white precipitate, performing ultrasonic dispersion and centrifugal washing respectively by using absolute ethyl alcohol and deionized water, and drying to collect white powder;

step four, transferring the collected white powder into a tube furnace, annealing in an argon atmosphere, and cooling to room temperature to obtain ZnMoO₄An electroactive material.

Further, in the first step, the molar ratio of zinc nitrate hexahydrate, sodium molybdate dihydrate, ammonium fluoride and urea is a: b: c: d, wherein a is more than or equal to 0 and less than or equal to 2; b is more than or equal to 0 and less than or equal to 2; c is more than or equal to 0 and less than or equal to 4; d is more than or equal to 0 and less than or equal to 5.

Further, in the first step, the mixed solvent is formed by mixing deionized water and ethanol according to a certain proportion.

Further, the volume ratio of the deionized water to the ethanol in the mixed solvent is x: y, wherein x is more than or equal to 1 and less than or equal to 3; y is more than or equal to 0 and less than or equal to 2.

Further, in the second step, the step of placing the reaction kettle into an oven for heating, wherein the step of preserving heat for a period of time comprises: and (3) putting the reaction kettle into an oven to be heated at 160 ℃, and preserving heat for 10-12 h.

Further, in the third step, the ultrasonic dispersion centrifugal washing with absolute ethyl alcohol and deionized water respectively comprises: and (3) ultrasonically dispersing and centrifugally washing the white precipitate for 3-5 times by respectively using absolute ethyl alcohol and water.

Further, in step three, the centrifuging comprises: the centrifugal speed is 5000-8500 r/min, and the centrifugal time is 6-10 min.

Further, in the fourth step, the annealing treatment includes: the heating rate is 1-5 ℃/min, the annealing temperature is 400-450 ℃, and the constant temperature time is 2-4 h.

According to a certain parameter ratio, the invention can control the morphology synthesis to obtain the required nano-sheet structure.

It is another object of the present invention to provide a method for using the ZnMoO₄ZnMoO prepared by preparation method of electroactive material₄An electroactive material.

It is another object of the present invention to provide the ZnMoO₄The electroactive material is used as a negative electrode material of a lithium ion battery.

By combining all the technical schemes, the invention has the advantages and positive effects that: the invention discloses a simple one-step solvothermal synthesis method of ZnMoO₄Methods of electroactive materials. The organic solvent ethanol is added to influence the interaction between ions in the solution, and finally the ZnMoO with an obvious layered structure is obtained₄The nanometer material can increase the effective specific surface area of the material and the utilization rate of the active material. ZnMoO of the invention₄The gaps among the nano sheets shorten the diffusion path of lithium ions, and are beneficial to the insertion and extraction of the lithium ions, so that the electrochemical performance of the electrode material is improved.

The ZnMoO prepared by the invention has the advantages of low cost of required raw materials, simple preparation method, easy operation and good repeatability₄The material has high crystallinity and purity. ZnMoO prepared by the invention₄The negative electrode material has higher specific capacity and rate capability in the lithium ion battery.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments of the present application will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present application, and it is obvious for those skilled in the art that other drawings can be obtained from the drawings without creative efforts.

FIG. 1 shows ZnMoO provided in an embodiment of the present invention₄A flow chart of a method of making an electroactive material.

FIG. 2 is the ZnMoO prepared in example 1 and example 2 provided by the examples of the invention₄A Scanning Electron Microscope (SEM) image of the electroactive material.

FIG. 3 is the ZnMoO prepared in example 2 provided by the examples of the invention₄An X-ray diffraction (XRD) pattern of the electroactive material.

FIG. 4 is the ZnMoO prepared in example 2 provided by the examples of the invention₄The specific capacity-voltage curve of the electroactive material as the lithium ion battery negative electrode material for the first 4 cycles.

FIG. 5 is the ZnMoO prepared in example 2 provided by the examples of the invention₄Rate performance curve of electroactive material as negative electrode material of lithium ion battery.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Aiming at the problems in the prior art, the invention provides ZnMoO₄The invention relates to an electroactive material, a preparation method and application thereof, which are described in detail in the following with reference to the accompanying drawings.

As shown in FIG. 1, the ZnMoO provided by the embodiment of the invention₄The preparation method of the electroactive material comprises the following steps:

s101, weighing zinc nitrate hexahydrate, sodium molybdate dihydrate, ammonium fluoride and urea according to a certain proportion, and ultrasonically dissolving the weighed materials in a mixed solvent formed by mixing deionized water and ethanol according to a certain proportion to obtain a mixed solution;

s102, transferring the obtained mixed solution into a stainless steel high-pressure reaction kettle, putting the reaction kettle into an oven, heating at 160 ℃, and preserving heat for 10-12 hours;

s103, after the reaction kettle is cooled to room temperature, centrifuging to obtain a white precipitate, performing ultrasonic dispersion and centrifugal washing for 3-5 times by using absolute ethyl alcohol and deionized water respectively, and drying to collect white powder;

s104, transferring the collected white powder to a tube furnace, annealing in an argon atmosphere, and cooling to room temperature to obtain ZnMoO₄An electroactive material.

In step S101, the molar ratio of zinc nitrate hexahydrate, sodium molybdate dihydrate, ammonium fluoride and urea provided in the embodiment of the present invention is a: b: c: d, where a is greater than or equal to 0 and less than or equal to 2; b is more than or equal to 0 and less than or equal to 2; c is more than or equal to 0 and less than or equal to 4; d is more than or equal to 0 and less than or equal to 5.

In step S101, the volume ratio of deionized water to ethanol in the mixed solvent provided in the embodiment of the present invention is x: y, wherein x is more than or equal to 1 and less than or equal to 3; y is more than or equal to 0 and less than or equal to 2.

In step S103, the centrifugation provided in the embodiment of the present invention includes: the centrifugal speed is 5000-8500 r/min, and the centrifugal time is 6-10 min.

In step S104, the annealing process provided in the embodiment of the present invention includes: the heating rate is 1-5 ℃/min, the annealing temperature is 400-450 ℃, and the constant temperature time is 2-4 h.

The technical solution of the present invention is further described below with reference to specific examples.

Example 1:

the embodiment of the invention provides ZnMoO for a lithium ion battery cathode₄The preparation method of the electroactive material comprises the following steps:

first, 298mg of zinc nitrate hexahydrate, 242mg of sodium molybdate dihydrate, 150mg of ammonium fluoride and 300mg of urea were added to 30mL of deionized water; ultrasonically dissolving the mixture at room temperature, magnetically stirring for 10min, transferring the mixed solution into a stainless steel high-pressure reaction kettle, putting the high-pressure reaction kettle into a drying oven at 160 ℃, and preserving heat for 12 h; and after the high-pressure reaction kettle is naturally cooled to room temperature, centrifugally washing the mixture to obtain a white precipitate, ultrasonically treating the white precipitate, washing the white precipitate for a plurality of times by using absolute ethyl alcohol and deionized water, and centrifugally collecting a product to obtain white powder. Finally, the obtained white powder is transferred to a tube furnace, annealing treatment is carried out in an argon atmosphere, and ZnMoO can be obtained after cooling to room temperature₄An electroactive material.

Example 2:

the embodiment of the invention provides ZnMoO for a lithium ion battery cathode₄The preparation method of the electroactive material comprises the following steps:

first, 298mg of zinc nitrate hexahydrate,242mg of sodium molybdate dihydrate, 150mg of ammonium fluoride and 300mg of urea are added into 30mL of a mixed solution of deionized water and ethanol (the volume ratio of the deionized water to the ethanol is 2: 1); ultrasonically dissolving the mixture at room temperature, magnetically stirring for 10min, transferring the mixed solution into a stainless steel high-pressure reaction kettle, putting the high-pressure reaction kettle into a drying oven at 160 ℃, and preserving heat for 12 h; and after the high-pressure reaction kettle is naturally cooled to room temperature, centrifugally washing the mixture to obtain a white precipitate, ultrasonically treating the white precipitate, washing the white precipitate for a plurality of times by using absolute ethyl alcohol and deionized water, and centrifugally collecting a product to obtain white powder. Finally, the obtained white powder is transferred to a tube furnace, annealing treatment is carried out in an argon atmosphere, and ZnMoO can be obtained after cooling to room temperature₄An electroactive material.

Example 3:

the embodiment of the invention provides ZnMoO for a lithium ion battery cathode₄The preparation method of the electroactive material comprises the following steps:

first, 298mg of zinc nitrate hexahydrate, 242mg of sodium molybdate dihydrate, 150mg of ammonium fluoride and 300mg of urea were added to 30mL of a mixed solution of deionized water and ethanol (the volume ratio of deionized water to ethanol was 1: 1); ultrasonically dissolving the mixture at room temperature, magnetically stirring for 10min, transferring the mixed solution into a stainless steel high-pressure reaction kettle, putting the high-pressure reaction kettle into a drying oven at 160 ℃, and preserving heat for 12 h; and after the high-pressure reaction kettle is naturally cooled to room temperature, centrifugally washing the mixture to obtain a white precipitate, ultrasonically treating the white precipitate, washing the white precipitate for a plurality of times by using absolute ethyl alcohol and deionized water, and centrifugally collecting a product to obtain white powder. Finally, the obtained white powder is transferred to a tube furnace, annealing treatment is carried out in an argon atmosphere, and ZnMoO can be obtained after cooling to room temperature₄An electroactive material.

Example 4:

the embodiment of the invention provides ZnMoO for a lithium ion battery cathode₄The preparation method of the electroactive material comprises the following steps:

first, 298mg of zinc nitrate hexahydrate, 242mg of sodium molybdate dihydrate, 150mg of ammonium fluoride and 300mg of urea are added into 30mL of a mixed solution of deionized water and ethanol (the volume ratio of the deionized water to the ethanol is 1: 2); ultrasonically dissolving the mixture at room temperature, magnetically stirring for 10min, transferring the mixed solution into a stainless steel high-pressure reaction kettle, putting the high-pressure reaction kettle into a drying oven at 160 ℃, and preserving heat for 12 h; and after the high-pressure reaction kettle is naturally cooled to room temperature, centrifugally washing the mixture to obtain a white precipitate, ultrasonically treating the white precipitate, washing the white precipitate for a plurality of times by using absolute ethyl alcohol and deionized water, and centrifugally collecting a product to obtain white powder. Finally, the obtained white powder is transferred to a tube furnace, annealing treatment is carried out in an argon atmosphere, and ZnMoO can be obtained after cooling to room temperature₄An electroactive material.

Comparative example:

the invention provides a ZnMoO used for a lithium ion battery cathode in a comparative example₄The preparation method of the electroactive material comprises the following steps:

firstly, 594mg of zinc nitrate hexahydrate and 484mg of sodium molybdate dihydrate are respectively added into 20mL of deionized water; then mixing the two solutions, ultrasonically dissolving the mixture at room temperature, then magnetically stirring for 10min, transferring the mixed solution into a stainless steel high-pressure reaction kettle, putting the high-pressure reaction kettle into a drying oven at the temperature of 150 ℃, and preserving heat for 12 h; after the high-pressure reaction kettle is naturally cooled to room temperature, centrifugally washing the mixture to obtain white precipitate, ultrasonically treating the white precipitate, washing the white precipitate for a plurality of times by using absolute ethyl alcohol and deionized water, centrifugally collecting the product to obtain ZnMoO₄An electroactive material.

Compared with the prior art, the invention provides ZnMoO for the cathode of the lithium ion battery₄The preparation method of the electroactive material and the addition of the organic solvent ethanol influence the interaction between ions in the solution, and finally the ZnMoO with an obvious layered structure is obtained₄The nanometer material can increase the effective specific surface area of the material and the utilization rate of the active material. ZnMoO₄The gaps between the nano sheets shorten the diffusion path of lithium ions, and are favorable for the insertion and extraction of the lithium ionsThereby improving the electrochemical performance of the electrode material. The ZnMoO prepared by the invention has the advantages of low cost of required raw materials, simple preparation method, easy operation and good repeatability₄The material has high crystallinity and purity.

Table 1 performance parameters of electrode materials prepared in examples 1 to 4 and comparative examples

The above description is only for the purpose of illustrating the present invention and the appended claims are not to be construed as limiting the scope of the invention, which is intended to cover all modifications, equivalents and improvements that are within the spirit and scope of the invention as defined by the appended claims.