CN104900906B - Vanadium-based compound Zn3V3O8, as well as preparation method and application of vanadium-based compound Zn3V3O8 - Google Patents

Abstract

The invention provides a vanadium-based compound. The chemical formula of the vanadium-based compound is Zn ₃ V ₃ O ₈ . Weigh 2 mmol and 1 mmol of vanadium respectively, and then weigh 5 mmol of hexamethylenetetramine; place the raw materials in a beaker and add distilled water to stir for 30 minutes to form a uniform solution; transfer the uniform solution to a hydrothermal reaction kettle at 160 React at ℃ for 12~24 hours, centrifuge, dry and collect the reaction product, and sinter at 600℃ for 5~10 hours under a nitrogen protective atmosphere to obtain the vanadium-based compound zinc vanadate Zn ₃ V ₃ O ₈ . The synthesis method of the method is simple and the cost is low; the prepared Zn ₃ V ₃ O ₈ is composed of micro-sheets and nanoparticles, the average thickness of the micro-sheets is about 200nm, and the average size of the nanoparticles is about 100nm. The prepared Zn ₃ V ₃ O ₈ can be used as negative electrode material of lithium ion battery.

Description

A vanadium-based compound zinc vanadate and its preparation method and application

technical field

The invention relates to a preparation method of a novel lithium ion battery negative electrode material, in particular to a preparation method of a lithium ion battery negative electrode material zinc vanadate, which belongs to the field of new electrochemical materials.

technical background:

Lithium-ion batteries have the advantages of high working voltage, high specific capacity, large specific power, stable charge and discharge potential curve, long cycle life, no memory effect, small self-discharge, and environmental friendliness. The third generation of small batteries are widely used in mobile portable devices such as notebook computers and mobile phones. In addition, lithium-ion batteries are also considered to be an ideal power source for future electric vehicles. In the future, the research direction of lithium-ion batteries will mainly focus on the development of high specific energy and high-power lithium-ion batteries, and the key lies in the design and preparation of electrode materials with high capacity and superior rate performance. At present, the cathode materials of lithium-ion batteries are mainly transition metal compounds containing lithium, and the system is relatively abundant. However, the types of negative electrode materials are relatively scarce, mainly graphite-like carbon. The development of new anode materials is of great significance for the development of lithium-ion batteries. Among all kinds of new negative electrode materials, vanadium-based compound materials have always played an important role in the development of lithium-ion batteries due to their low cost, abundant reserves, and multi-valence states, such as LiVO ₂ , Li ₃ VO ₄ , CoV ₂ O ₆ etc. have shown good electrochemical performance as anode materials for lithium ion batteries.

As a typical vanadium-based compound material, zinc vanadate has been partially reported in the field of lithium-ion batteries and supercapacitors. For example: the literature [J. Sun, CS Li, LN Wang and YZ Wang, RSCAdv., 2012, 2, 8110] reported the electrochemical performance of ZnV ₂ O ₆ as a negative electrode material for lithium-ion batteries, [LH G, DR Deng , YJ Zhang, G. Li, XY Wang, L. Jiang and CR Wang J. Mater.Chem. A, 2014, 2, 2461] reported the electrochemical performance of Zn ₃ V ₂ O ₈ as a negative electrode material for lithium-ion batteries , ZnV ₂ O ₄ Electrochemical performance as a negative electrode material for lithium-ion batteries, the literature [Nulu Venugopal and Woo-Sik Kim, DOI10.1007/s11814-014-0392-9] reported the electrochemical performance of ZnV ₂ O ₄ as a supercapacitor electrode material .

At present, there are few studies on the preparation of Zn ₃ V ₃ O ₈ materials, and the research on its electrochemical performance has not been reported. Based on the above background, this patent invented a new method for preparing Zn ₃ V ₃ O ₈ material, which shows a clear charge and discharge platform as a negative electrode material for lithium ion batteries, indicating that it has potential application value in lithium ion batteries.

purpose of invention

The object of the present invention is to use zinc acetate, vanadium pentoxide and hexamethylenetetramine as raw materials to prepare vanadium-based compound Zn ₃ V ₃ O ₈ which can be used as negative electrode material of lithium ion battery through hydrothermal and solid phase sintering. The principle is to use hydrothermal reaction to prepare Zn ₃ V ₃ O ₈ precursor, and then use solid phase sintering to prepare Zn ₃ V ₃ O ₈ with good crystallization properties.

The specific steps of the preparation method of the zinc vanadate Zn ₃ V ₃ O ₈ are:

(1) Weigh 2 mmol and 1 mmol of zinc acetate and vanadium pentoxide with a purity of more than 99.9%, respectively, and then weigh 5 mmol of hexamethylenetetramine;

(2) Place the raw materials in step (1) in a beaker and add distilled water to stir for 30 minutes to form a uniform solution;

(3) Transfer the homogenate and solution of step (2) to a hydrothermal reaction kettle and react at 160°C for 12-24 hours, centrifuge, dry and collect the reaction product;

(4) The product collected in step (3) was sintered at 600°C for 5-10 h under a nitrogen atmosphere to obtain the vanadium-based compound zinc vanadate Zn ₃ V ₃ O ₈ .

The present invention also provides the application of the above-mentioned vanadium-based compound Zn ₃ V ₃ O ₈ in negative electrode materials of lithium ion batteries.

The vanadium-based compound Zn ₃ V ₃ O ₈ material, preparation method and application involved in the present invention have the following remarkable features:

(1) The synthesis method is simple and the cost is low;

(2) The prepared Zn ₃ V ₃ O ₈ is composed of micro-sheets and nanoparticles, the average thickness of the micro-sheets is about 200nm, and the average size of the nanoparticles is about 100nm.

(3) The prepared Zn ₃ V ₃ O ₈ can be used as anode material for lithium-ion batteries.

Description of drawings:

The XRD pattern of the sample prepared in Fig. 1 embodiment.

The SEM figure of the sample prepared in Fig. 2 embodiment.

Figure 3 is the first charge and discharge curve (a) and cycle performance graph (b) of the sample prepared in the embodiment.

detailed description:

Example:

The material synthesis steps are as follows:

(1) Weigh 2 mmol and 1 mmol of zinc acetate and vanadium pentoxide with a purity of more than 99.9%, respectively, and then weigh 5 mmol of hexamethylenetetramine;

(2) Place the raw materials in step (1) in a beaker and add distilled water to stir for 30 minutes to form a uniform solution;

(3) Transfer the homogenate and the solution of step (2) to a hydrothermal reaction kettle and react at 160°C for 24 hours, centrifuge, dry and collect the reaction product;

(4) The product collected in step (3) was sintered at 600 °C for 5 h under nitrogen protection atmosphere.

The prepared sample was analyzed by XRD pattern, and the results showed that: except for the diffraction peaks at 31.8°, 34.5°, 36.4° and 47.7 ^o , the diffraction peaks corresponded to (100), (002), (101) of the ZnO standard card JCPDS, no. 75-0567 ) and (102) crystal plane, the remaining diffraction peaks can well correspond to the standard card JCPDS of cubic Zn ₃ V ₃ O ₈ , no. 31-1477. The as-prepared samples were characterized by SEM, as shown in Figure 2(a), consisting of a large number of flake-like morphology and particles. The diameter distribution of flakes is about 2 ~ 5 μm, and the thickness is about 200 nm. Further enlarged from Figure 2(b), it can be seen that the particle size is about 100 nm. The materials obtained in the examples are made into batteries as follows: the prepared Zn ₃ V ₃ O ₈ samples are mixed with acetylene black and polyvinylidene fluoride in a weight ratio of 8:1:1, and N-methyl Pyrrolidone was used as a solvent to make a slurry, coated on a copper foil with a thickness of 10 μm, dried at 60 °C for 10 h, cut into 14 mm discs, and dried in vacuum at 120 °C for 12 h. The metal lithium sheet is used as the counter electrode, the Celgard membrane is used as the diaphragm, and the solution of EC+DMC+DEC (volume ratio 1:1:1) dissolved in LiPF ₆ (1mol/L) is used as the electrolyte solution, and the argon-protected gloves The box is assembled into a CR2025 battery. After the battery is assembled, let it stand for 8 hours, and then use the CT2001A battery test system to conduct a constant current charge and discharge test with a test voltage of 3~0.02V. Figure 3 shows the initial charge and discharge curves and cycle performance of the prepared Zn ₃ V ₃ O ₈ sheet-shaped lithium-ion battery anode material. The first charge and discharge specific capacities are 732.6 and 1845.1 mAh/g respectively. The charge and discharge capacities are 183.8 and 188.3 mAh/g, respectively, indicating that it has potential application value in lithium-ion batteries.

Claims (1)

1. A vanadium-based compound, characterized in that, the chemical formula of the vanadium-based compound is Zn ₃ V ₃ O ₈ , which is in the form of microsheets and nanoparticles, The specific steps of the preparation method of the zinc vanadate Zn ₃ V ₃ O ₈ are: (1) Weigh 2 mmol and 1 mmol of zinc acetate and vanadium pentoxide with a purity of more than 99.9%, respectively, and then weigh 5 mmol of hexamethylenetetramine; (2) Place the raw materials in step (1) in a beaker and add distilled water to stir for 30 minutes to form a uniform solution; (3) Transfer the homogeneous solution of step (2) to a hydrothermal reaction kettle and react at 160°C for 12-24 h, centrifuge, dry and collect the reaction product; (4) Sinter the product collected in step (3) at 600°C for 5-10 h under a nitrogen protective atmosphere to obtain the vanadium-based compound zinc vanadate Zn ₃ V ₃ O ₈ , the vanadium-based compound Zn ₃ V ₃ Application of O ₈ in lithium-ion battery anode materials.