CN111807424B - Granular NiMoO 4 Preparation method of electrode material - Google Patents

Abstract

The invention discloses a preparation method of granular NiMoO ₄ electrode material, belonging to the field of lithium ion battery negative electrode material and nanometer material. Synthesis steps of this granular electrode material: a. Nickel chloride hexahydrate and molybdenum acetylacetonate are added to ethanol; b. put in an oven for reaction; c. washed with ethanol and water; d. dried in a vacuum drying oven ; e. The precursor material was annealed at high temperature in air to obtain NiMoO ₄ electrode material. The key to the synthesis method of the present invention is the temperature of the reaction, the time and the temperature of the annealing treatment. Compared with other NiMoO ₄ lithium ion negative electrode materials, the NiMoO ₄ electrode material has relatively good electrochemical performance and can be applied to electric vehicles. The composite electrode material has the advantages of simple preparation method, short reaction time and novel material.

Description

A kind of preparation method of granular NiMoO4 electrode material

technical field

The invention relates to the technical field of preparation of lithium ion power battery electrode materials and nanomaterials, in particular to a preparation method of a granular NiMoO ₄ electrode material.

Background technique

Today, the energy density and power density of commercialized nickel-hydrogen, alkaline zinc-manganese and other secondary batteries can no longer meet the needs of large-scale energy storage devices. At the same time, they also have problems such as difficult recycling, poor portability, and unfriendly environment. New battery systems (lithium-air batteries, lithium-sulfur batteries, fuel cells, zinc-ion batteries, and magnesium-ion batteries) still have many cycle performance and safety performance issues, so the road to commercialization is still far away. Lithium-ion batteries with high specific energy, high charging efficiency, long cycle life, low self-discharge and relatively low price have been widely used in various large electronic products (aerospace, electric vehicles) and portable electronic products (mobile phones, It has gradually become the mainstream of secondary batteries. However, with the improvement of people's living standards, there is an urgent need for lithium-ion batteries with higher power density and energy density and long cycle life to adapt to modern large-scale electrical equipment, such as pure electric vehicles, high-energy-density mobile power supplies, large-scale smart Electric grids and hybrid vehicles, etc.

Molybdenum-based oxides have been widely used in various fields such as gas separation/storage, sewage treatment, optical devices, and energy storage. In particular, materials with regular morphology can be obtained by adjusting the reaction conditions. Many literatures have reported that molybdenum-based oxides with uniform and regular structure can have excellent electrochemical performance. In addition, molybdenum-based sulfides or molybdenum-based selenides obtained by mixing molybdenum-based oxides with sulfur powder or selenium for sulfidation or selenization have also been extensively studied, and they have achieved good results in energy storage.

The current research on lithium ion anode materials is mainly focused on the development of transition metal oxides and transition metal sulfides with different morphologies, and good results have been achieved. However, there are few studies on molybdates, especially molybdates based on nickel metal. Compared with the nickel molybdate materials obtained by other methods, the nickel molybdate obtained by the simple hydrothermal method has higher capacity, which is mainly attributed to its ability to maintain a good structure.

SUMMARY OF THE INVENTION

The main purpose of the present invention is to provide a coil device with a heating device, which can effectively solve the problems in the background technology.

To achieve the above object, the technical scheme adopted in the present invention is:

1. a preparation method of granular _NiMoO electrode material, is characterized in that, comprises the following steps:

a. Weigh a certain amount of nickel chloride hexahydrate and molybdenum acetylacetonate and mix them into the ethanol, and stir until the solid is completely dissolved;

b. Transfer the above solution to a polytetrafluoroethylene-lined reactor, and place it in an oven for heating;

c. The above reaction product is washed with ethanol and water to remove unreacted ions; the washed reaction product is centrifuged with a centrifuge, and the obtained product is placed in a vacuum drying box to dry, and after drying, an electrode is obtained precursor material;

d. The precursor material is placed in a ceramic boat, and the electrode material NiMoO ₄ is obtained by annealing treatment at 500° C. in an air atmosphere.

e. Take the conductive carbon black and PVDF adhesive and the above-mentioned electrode material NiMoO ₄ and mix them evenly in a mass ratio of 8:1:1, then add N,N-dimethylpyrrolidone to the mixture, and use a high-speed internal rotary beater Disperse the slurry to obtain a black colloidal slurry;

f. The black colloidal slurry obtained above is evenly coated on the copper foil, and then the copper foil is dried in a vacuum oven, and the electrode of the lithium ion battery can be obtained after drying.

Preferably, in the described step a), the nickel chloride hexahydrate is 0.7131 g, the molybdenum acetylacetonate is 0.3262 g, the ethanol is 50 mL, and the stirring time is 30 min.

Preferably, in the step b), the baking temperature of the oven is 200° C., and the baking time is 48 h.

Compared with the prior art, the present invention is to synthesize granular nickel molybdate precursor material through a one-step hydrothermal method, obtain the final material through high temperature annealing treatment, and then mechanically disperse the prepared composite electrode material slurry, and then dry it in a vacuum drying oven. to obtain the final electrode material. The electrochemical tests show that the new particle-structured _NiMoO4 composite electrode material has excellent electrochemical performance (high specific capacity and long cycle life). At the same time, this particle-structured NiMoO ₄ composite electrode material has the advantages of simple preparation method, low cost, unique and novel material, etc., and has certain potential for commercial practical application.

Description of drawings

Fig. 1 is the X-ray diffraction (XRD) pattern of the present invention;

Fig. 2 is the scanning electron microscope image of granular _NiMoO electrode material of the present invention;

Fig. 3 is the TEM image of granular _NiMoO electrode material of the present invention;

FIG. 4 is a charge-discharge curve diagram of the granular NiMoO ₄ electrode material of the present invention at a current density of 100 mA g-1;

FIG. 5 is a cycle curve diagram of the granular NiMoO4 electrode material of the present invention at a current density of 100 mA g-1;

FIG. 6 is a graph showing the magnification rate of the granular NiMoO4 electrode material of the present invention at a current density of 100 mA g-1.

Detailed ways

In order to make the technical means, creative features, achievement goals and effects realized by the present invention easy to understand, the present invention will be further described below with reference to the specific embodiments.

Referring to Fig. 1 to Fig. 6, a preparation method of a granular _NiMoO4 electrode material of the present invention, the steps are as follows:

a. Weigh 0.7131 g of nickel chloride hexahydrate and 0.3262 g of molybdenum acetylacetonate, add them to 50 mL of ethanol, and stir for 30 min to completely dissolve the solid.

b. The above solution was transferred to an 80 mL polytetrafluoroethylene-lined reactor, placed in an oven, and reacted at 200 °C for 48 h.

c. Wash the above reaction product with ethanol and water to remove unreacted ions. The product obtained by centrifugation is dried in a vacuum drying oven, and after drying, a precursor material is obtained.

d. The precursor material was placed in a ceramic boat, and annealed at 500°C for 3 h in an air atmosphere to obtain an electrode material (NiMoO ₄ ).

e. Mix NiMoO ₄ electrode material, conductive carbon black (Super P) and PVDF adhesive in a mass ratio of 8:1:1, then add N,N-dimethylpyrrolidone to the mixture, and use a high-speed internal rotary The beater disperses the slurry, repeating 5-10 times per minute to obtain a uniform black colloidal slurry.

f. The black colloidal slurry obtained above was evenly coated on the pre-treated copper foil, and dried in a vacuum oven at a temperature of 60 °C and a drying time of 12 h to prepare electrodes for lithium ion batteries.

Assembly of the battery and its testing:

The above-prepared electrodes to be tested were assembled into a button battery for evaluation. Lithium foil was used as the reference electrode, polypropylene porous membrane (Celgard 2300) was used as the separator, and the electrolyte was a mixed solution of 1 mol/L LiPF ₆ and ethylene carbonate and diethyl carbonate (w/w, 1/1). , assemble the cells in a glove box filled with high-purity argon. On the LAND-CT2001C system, the cells were subjected to lithium intercalation and delithiation cycles at different currents in a fixed potential range (1 mV–3.0 V vs. Li ⁺ /Li). The test current density was 100 mA g ^-1 and the test voltage range was 5 mV-3.0 V.

As shown in the XRD pattern of the Fe-CrSe/C composite electrode in Fig. 1, it is found that the product is a NiMoO ₄ compound after analysis. Figures 2 and 3 are the scanning and transmission electron microscope photos of the _NiMoO4 composite electrode. It can be seen that the _NiMoO4 material is a granular nanoparticle with a particle diameter of about 10-40 nm. Figure 4 shows the charge-discharge curve of the NiMoO ₄ composite electrode, and the reaction platform can be clearly seen from the first circle of the curve. At the same time, the Coulombic efficiency of the _NiMoO4 composite electrode is 68.2%, and the main reason for the low Coulombic efficiency is the formation of the solid electrolyte interface film. Figure 5 shows the cycling curve of the NiMoO ₄ composite electrode at a current density of 100 mA g ^-1 . It can be seen that the cycling becomes stable after the capacity decreases in the first 50 cycles, and reaches 829 mAh g ^-1 after 250 cycles. Figure 6 shows the rate curves of the NiMoO ₄ composite electrode. It can be seen that the electrode has a capacity as high as 600, 529 and 412 mAh g ^-1 at high currents of 1C, 2C, and 5C, respectively.

The basic principles and main features of the present invention and the advantages of the present invention have been shown and described above. Those skilled in the art should understand that the present invention is not limited by the above-mentioned embodiments. The above-mentioned embodiments and descriptions only illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will also have Various changes and modifications fall within the scope of the claimed invention. The claimed scope of the present invention is defined by the appended claims and their equivalents.

Claims (1)

1. a preparation method of granular _NiMoO electrode material, is characterized in that, comprises the following steps: a. Weigh a certain amount of nickel chloride hexahydrate and molybdenum acetylacetonate and mix them into the ethanol, and stir until the solid is completely dissolved; b. Transfer the above solution to a polytetrafluoroethylene-lined reactor, and place it in an oven for heating; c. The above reaction product is washed with ethanol and water to remove unreacted ions; the washed reaction product is centrifuged with a centrifuge, and the obtained product is placed in a vacuum drying box to dry, and after drying, an electrode is obtained precursor material; d. Place the precursor material in a porcelain boat, and perform annealing treatment at 500° C. in an air atmosphere to obtain an electrode material NiMoO ₄ . The NiMoO ₄ material is granular nano-particles with a particle diameter of 10-40 nm; e. Take the conductive carbon black and PVDF adhesive and the above-mentioned electrode material NiMoO ₄ and mix them evenly in a mass ratio of 8:1:1, then add N,N-dimethylpyrrolidone to the mixture, and use a high-speed internal rotary beater Disperse the slurry to obtain a black colloidal slurry; f. The black colloidal slurry obtained above is evenly coated on the copper foil, and then the copper foil is placed in a vacuum oven to dry, and the electrode of the lithium ion battery can be obtained after drying; In described step a), nickel chloride hexahydrate is 0.7131 g, molybdenum acetylacetonate is 0.3262 g, ethanol is 50 mL, and stirring time is 30 min; In the step b), the baking temperature of the oven is 200° C., and the baking time is 48 h.

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