CN107394188B - A kind of preparation method of hollow spherical niobium oxide electrode material for lithium ion battery - Google Patents

Abstract

A method for preparing a hollow spherical niobium oxide electrode material for lithium ion batteries. First, analytically pure hydrated niobium oxalate is added to a hydrochloric acid solution to obtain A; rape pollen is suspended in the hydrochloric acid solution to obtain B; B is washed with water and alcohol, and then placed In the petri dish, add cetyl trimethyl ammonium bromide to it again to obtain C; A and C are added to the reactor, and after sealing, a hydrothermal reaction is carried out in a homogeneous reactor, and after the reaction is finished, it is naturally cooled to After precipitation at room temperature; the precipitate was washed with water and alcohol, and then placed in a petri dish, transferred to a vacuum dryer for vacuum drying to obtain D; the precursor D was taken in a dry pot, heat-treated under the protection of oxygen, and then cooled with the furnace, The target product Nb ₂ O ₅ is obtained. The invention adopts the hydrothermal calcination and sintering method to efficiently and rapidly prepare hollow spherical Nb ₂ O ₅ crystals with uniform distribution and good crystallinity. Using rape pollen as the template of Nb ₂ O ₅ has the advantages of simple production process, low cost, green environmental protection, and is beneficial to control the structure and morphology of the prepared material.

Description

A kind of preparation method of hollow spherical niobium oxide electrode material for lithium ion battery

technical field

The invention belongs to the technical field of battery materials, and relates to a method for preparing a positive electrode material for a lithium ion battery, in particular to a method for preparing a hollow spherical niobium oxide electrode material for a lithium ion battery.

Background technique

As an efficient energy storage device, lithium-ion battery has high energy density, long service life, good safety performance, etc. in the process of use. It can not only be used many times, but also has no pollution to the environment. Ideal "green" chemical energy [Sun Xueliang, Qin Xiujuan, Bu Limin, et al. Research progress of carbon anode materials for lithium ion batteries [J]. Nonferrous Metal Engineering, 2011,63(2):147-151]. The structure of a lithium-ion battery is mainly composed of four parts: positive electrode material, electrolyte, separator, and negative electrode material. The electrode material accounts for the highest proportion in the manufacturing cost of the battery, and the electrode material is closely related to the specific capacity and cycle life of the battery. Therefore, in the study of lithium-ion batteries, the study of electrode materials has always been a research hotspot.

At present, the cathode materials of lithium ion batteries are usually lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, manganese nickel cobalt composite oxide, lithium vanadium oxide, lithium iron oxide, etc. The cathode materials generally use LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ , LiCoO ₂ , LiMn ₂ O ₄ [Zhang Hui, Zheng Fengang, Li Decheng, et al. Preparation and electrochemical properties of new lithium battery cathode materials [J]. Power Technology, 2013, 37(3):366-369], but its theoretical capacity is smaller, the actual capacity is smaller, and there are a series of influences in the process of use. The cost of cathode materials is the highest in the production process of lithium-ion batteries, and the capacity of cathode materials is much lower than that of anode materials. At the same time, the electrochemical performance of lithium-ion batteries depends largely on the structure of cathode materials. Therefore, in recent years, cathode materials have become a hot spot in lithium-ion battery research. Nb-based oxides have relatively high capacity and have great potential as cathode materials for lithium-ion batteries. Nb-based oxides mainly include: Nb ₂ O ₅ , NbO ₂ , Nb ₂ O ₃ and NbO, among which Nb ₂ O ₅ is relatively the most stable.

Dunn [Kim JW, Augustyn V, Dunn B. The effect of crystallinity on therapid pseudocapacitive response of Nb ₂ O ₅ [J]. Advanced Energy Materials, 2011, 2(1): 141-148] et al. Nb2O5 has a relatively high theoretical capacity and working potential window. Nb2O5 as a battery cathode material hardly deforms during the charging and discharging cycle of the battery, so it has little effect on the structure of the battery [Lou Shuaifeng, Cheng Xinqun, Ma Yulin, et al. Lithium-ion battery Niobium-based oxide anode material[J].Chemistry Progress,2015,27(2):000297-309], compared with traditional electrode materials, it is an ideal battery cathode material. However, due to the poor electrical conductivity of Nb ₂ O ₅ itself, its discharge performance at large rates is limited. Therefore, improving the electrical conductivity of Nb ₂ O ₅ will change the result, increase its reaction site, and increase its specific surface area. Thus, the rate capability and cycle performance of Nb ₂ O ₅ are improved.

By controlling the structure and morphology of Nb ₂ O ₅ , the cycling stability of Nb ₂ O ₅ electrode material can be greatly improved. However, the morphology of Nb ₂ O ₅ used in current reports is mostly nanorods, nanoparticles, and nanoblocks. , or require a complex preparation process, which greatly increases the production cost of electrode materials and is not conducive to mass production. Therefore, it is very important to develop a method for preparing Nb ₂ O ₅ electrode material with a special structure, which is beneficial to improve the conductivity of Nb ₂ O ₅ , with low cost and simple process.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the shortcomings of the above-mentioned existing structures, and to provide a method for preparing a hollow spherical niobium oxide electrode material for lithium ion batteries by heat treatment combined with hydrothermal calcination. By using the method of the invention, a hollow spherical Nb ₂ O ₅ electrode material with controllable morphology and uniform particle size can be prepared. In addition, the preparation process is simple, the reaction period is short, the cost is low, and the invention has broad development prospects.

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

1) First, add 0.80-1.0 g of analytically pure hydrated niobium oxalate to 30-70 ml of hydrochloric acid solution with a concentration of 0.1-0.5 mol/l, stir evenly, and then ultrasonically disperse to obtain a transparent solution A;

2) get 4.3-4.7g of rape pollen and be suspended in 10-50ml of hydrochloric acid solution with a concentration of 0.2-0.7mol/l, and stir to obtain mixed solution B;

3) After the mixed solution B was washed with water and alcohol, respectively, placed in a petri dish and then added 0.5-1 g of cetyltrimethylammonium bromide to it, and heated and stirred to obtain mixed solution C;

4) adding the gained transparent solution A and mixed solution C into the reactor, carrying out a hydrothermal reaction in a homogeneous reactor after sealing, and precipitation after the reaction is naturally cooled to room temperature;

5) The precipitate obtained in step 4) was washed with water and alcohol, and then placed in a petri dish, transferred to a vacuum dryer, and vacuum-dried at 100° C. to obtain precursor D;

6) Take the precursor D in a dry pot, and under the protection of oxygen, raise the temperature from room temperature to 500-600°C at a heating rate of 5°C/min for 5 hours, and then cool with the furnace to obtain the target product Nb ₂ O ₅ .

Described step 1) ultrasonic dispersion 60-120min.

In the step 4), the filling ratio in the reaction kettle is 30-60%, the reaction temperature of the homogeneous reactor is 80-120° C., and the reaction time is 11-15 h.

The beneficial effects of the present invention are embodied in:

1) The hollow spherical Nb ₂ O ₅ crystals with uniform distribution and good crystallinity are efficiently and rapidly prepared by the hydrothermal calcination and sintering method.

2) Rape pollen is used as the template of Nb ₂ O ₅ , the production process is simple, the cost is low, the environment is green, and the structure and morphology of the prepared material are controlled and controlled.

Description of drawings

FIG. 1 is the XRD pattern of the hollow spherical Nb ₂ O ₅ electrode material prepared in Example 1. FIG.

FIG. 2 is a SEM photograph of the hollow spherical Nb ₂ O ₅ electrode material prepared in Example 1. FIG.

FIG. 3 is a picture of the rate performance of the hollow spherical Nb ₂ O electrode material prepared in Example 1. FIG.

Detailed ways

Example 1:

1) First, add 0.80g of analytically pure hydrated niobium oxalate to 30ml of hydrochloric acid solution with a concentration of 0.1mol/l, stir evenly, and then ultrasonically disperse for 60min to obtain transparent solution A;

2) get the rape pollen of 4.3g and be suspended in the hydrochloric acid solution that 10ml concentration is 0.2mol/l, stir to obtain mixed solution B;

3) After the mixed solution B was washed with water and alcohol respectively, placed in a petri dish and then added 0.5g of cetyltrimethylammonium bromide (CTAB) therein, and heated and stirred to obtain mixed solution C;

4) Add the obtained transparent solution A and mixed solution C into the reaction kettle, control the filling ratio to be 30%, carry out hydrothermal reaction in a homogeneous reactor after sealing, control the reaction temperature to be 80°C, and the reaction time to be 11h, and the reaction After the end, it is naturally cooled to room temperature and precipitated;

5) The precipitate obtained in step 4) was washed with water and alcohol, and then placed in a petri dish, transferred to a vacuum dryer, and vacuum-dried at 100° C. to obtain precursor D;

6) Take the precursor D in a dry pot, under the protection of oxygen, from room temperature to 500 °C at a heating rate of 5 °C/min for 5 h, and then cooling with the furnace to obtain the target product Nb ₂ O ₅ .

It can be seen from Figure 1 that the Nb ₂ O ₅ electrode material was successfully prepared by the thermal calcination method. The diffraction peak of Nb ₂ O ₅ corresponds to the 27-1003 Nb ₂ O ₅ standard card.

It can be seen from Fig. 2 that the prepared Nb ₂ O ₅ composite electrode material is spherical with a plurality of hollow holes and uniform size.

Figure 3 is a picture of the rate performance of the prepared hollow spherical Nb ₂ O electrode material. At current densities of 50 mA, 100 mA, 200 mA, 500 mA, and 1000 mA, the specific capacities of the products were 220, 200, 190, 175, and 157 mAh· g ^-1 ; and when the current density returns to 50mA again, the specific capacity of the product can return to 217mAh·g ^-1 (98%), which shows that the Nb ₂ O ₅ cathode material has outstanding rate performance.

Example 2:

1) First, add 0.85g of analytically pure hydrated niobium oxalate to 40ml of hydrochloric acid solution with a concentration of 0.2mol/l, stir evenly, and then ultrasonically disperse for 80min to obtain transparent solution A;

2) get the rape pollen of 4.4g and be suspended in the hydrochloric acid solution that 20ml concentration is 0.3mol/l, stir to obtain mixed solution B;

3) After the mixed solution B was washed with water and alcohol respectively, placed in a petri dish and then added 0.6g of cetyltrimethylammonium bromide (CTAB) therein, and heated and stirred to obtain mixed solution C;

4) Add the obtained transparent solution A and mixed solution C into the reaction kettle, control the filling ratio to be 35%, carry out hydrothermal reaction in a homogeneous reactor after sealing, control the reaction temperature to be 90° C., and the reaction time to be 12h. After the end, it is naturally cooled to room temperature and precipitated;

5) The precipitate obtained in step 4) was washed with water and alcohol, and then placed in a petri dish, transferred to a vacuum dryer, and vacuum-dried at 100° C. to obtain precursor D;

6) Take the precursor D in a dry pot, and under the protection of oxygen, the temperature rises from room temperature to 525°C at a heating rate of 5°C/min for 5 hours, and then cooled with the furnace to obtain the target product Nb ₂ O ₅ .

Example 3:

1) First, add 0.90 g of analytically pure hydrated niobium oxalate to 50 ml of hydrochloric acid solution with a concentration of 0.3 mol/l, stir evenly, and then ultrasonically disperse for 100 min to obtain transparent solution A;

2) get the rape pollen of 4.5g and be suspended in the hydrochloric acid solution that 30ml concentration is 0.4mol/l, stir to obtain mixed solution B;

3) The mixed solution B is placed in a petri dish after washing with water and alcohol respectively and then adds 0.7g of cetyltrimethylammonium bromide (CTAB) therein, and heats and stirs to obtain mixed solution C;

4) Add the obtained transparent solution A and mixed solution C into the reaction kettle, control the filling ratio to be 40%, carry out the hydrothermal reaction in a homogeneous reactor after sealing, control the reaction temperature to be 100° C., and the reaction time to be 13h. After the end, it is naturally cooled to room temperature and precipitated;

5) The precipitate obtained in step 4) was washed with water and alcohol, and then placed in a petri dish, transferred to a vacuum dryer, and vacuum-dried at 100° C. to obtain precursor D;

6) Take the precursor D in a dry pot, and under the protection of oxygen, the temperature rises from room temperature to 550°C at a heating rate of 5°C/min for 5 hours, and then cooled with the furnace to obtain the target product Nb ₂ O ₅ .

Example 4:

1) First, add 0.95g of analytically pure hydrated niobium oxalate to 60ml of hydrochloric acid solution with a concentration of 0.4mol/l, stir evenly, and then ultrasonically disperse for 110min to obtain transparent solution A;

2) get the rape pollen of 4.6g and be suspended in the hydrochloric acid solution that 40ml concentration is 0.6mol/l, stir to obtain mixed solution B;

3) After the mixed solution B was washed with water and alcohol respectively, placed in a petri dish and then added 0.8g of cetyltrimethylammonium bromide (CTAB) therein, and heated and stirred to obtain mixed solution C;

4) Add the obtained transparent solution A and mixed solution C into the reaction kettle, control the filling ratio to be 50%, carry out hydrothermal reaction in a homogeneous reactor after sealing, control the reaction temperature to be 110° C., and the reaction time to be 14h. After the end, it is naturally cooled to room temperature and precipitated;

5) The precipitate obtained in step 4) was washed with water and alcohol, and then placed in a petri dish, transferred to a vacuum dryer, and vacuum-dried at 100° C. to obtain precursor D;

6) Take the precursor D in a dry pot, and under the protection of oxygen, the temperature rises from room temperature to 575°C at a heating rate of 5°C/min for 5 hours, and then cooled with the furnace to obtain the target product Nb ₂ O ₅ .

Example 5:

1) First, add 1.0 g of analytically pure hydrated niobium oxalate to 70 ml of hydrochloric acid solution with a concentration of 0.5 mol/l, stir evenly, and then ultrasonically disperse for 120 min to obtain transparent solution A;

2) get the rape pollen of 4.7g and be suspended in the hydrochloric acid solution that 50ml concentration is 0.7mol/l, stir to obtain mixed solution B;

3) After the mixed solution B was washed with water and alcohol respectively, placed in a petri dish and then added 1g of cetyltrimethylammonium bromide (CTAB) therein, and heated and stirred to obtain mixed solution C;

4) Add the obtained transparent solution A and mixed solution C into the reaction kettle, control the filling ratio to be 60%, carry out hydrothermal reaction in a homogeneous reactor after sealing, control the reaction temperature to be 120° C., and the reaction time to be 15h. After the end, it is naturally cooled to room temperature and precipitated;

5) The precipitate obtained in step 4) was washed with water and alcohol, and then placed in a petri dish, transferred to a vacuum dryer, and vacuum-dried at 100° C. to obtain precursor D;

6) Take the precursor D in a dry pot, under the protection of oxygen, from room temperature to 600°C at a heating rate of 5°C/min for 5 hours, and then cooling with the furnace to obtain the target product Nb ₂ O ₅ .

Claims (3)

1. A preparation method of a hollow spherical niobium oxide electrode material for a lithium ion battery is characterized by comprising the following steps:

1) firstly, 0.80-1.0g of analytically pure niobium oxalate hydrate is added into 30-70ml of hydrochloric acid solution with the concentration of 0.1-0.5mol/l, the mixture is uniformly stirred, and then the mixture is subjected to ultrasonic dispersion to obtain transparent solution A;

2) suspending 4.3-4.7g of rape pollen in 10-50ml of 0.2-0.7mol/l hydrochloric acid solution, and uniformly stirring to obtain a mixed solution B;

3) respectively washing the mixed solution B with water and alcohol, placing the washed mixed solution B into a culture dish, adding 0.5-1g of hexadecyl trimethyl ammonium bromide into the culture dish, and heating and uniformly stirring the mixture to obtain mixed solution C;

4) adding the obtained transparent solution A and the mixed solution C into a reaction kettle, sealing, carrying out hydrothermal reaction in a homogeneous reaction instrument, naturally cooling to room temperature after the reaction is finished, and precipitating;

5) washing the precipitate obtained in the step 4) with water and alcohol respectively, placing the washed precipitate in a culture dish, transferring the culture dish into a vacuum drier, and carrying out vacuum drying at the temperature of 100 ℃ to obtain a precursor D;

6) taking the precursor D in a dry pot, raising the temperature from room temperature to 500 ℃ and 600 ℃ at the heating rate of 5 ℃/min for processing for 5h under the protection of oxygen, and then cooling along with the furnace to obtain the target product Nb₂O₅。

2. The preparation method of the hollowed spherical niobium oxide electrode material for the lithium ion battery according to claim 1, wherein the method comprises the following steps: the step 1) ultrasonic dispersion is carried out for 60-120 min.

3. The preparation method of the hollowed spherical niobium oxide electrode material for the lithium ion battery according to claim 1, wherein the method comprises the following steps: the filling ratio in the reaction kettle in the step 4) is 30-60%, the reaction temperature of the homogeneous phase reactor is 80-120 ℃, and the reaction time is 11-15 h.

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