阅读说明：本技术 一种锂/钠离子电池负极材料四硒化三镍/碳复合材料及其制备方法 (Lithium/sodium ion battery cathode material nickel selenide/carbon composite material and preparation method thereof ) 是由 赵陈浩 沈圳 胡志彪 于 2019-09-27 设计创作，主要内容包括：本发明公开了一种锂/钠离子电池负极材料四硒化三镍/碳复合材料及其制备方法。该方法的步骤如下：1)将六水合氯化镍、柠檬酸和尿素共同置于乙醇和水的混合液中,水浴加热搅拌后干燥,获得镍盐前驱体；2)将镍盐前驱体先去除有机物,再高温碳化处理,获得镍/碳复合材料；3)将镍/碳复合材料研磨成镍/碳粉末后置于水中超声分散得溶液A,将硒粉加入到水中磁力搅拌,并加入硼氢化钠,得到溶液B；4)将溶液B加入溶液A中,水热反应后冷却,过滤、洗涤、干燥,获得Ni<Sub>3</Sub>Se<Sub>4</Sub>/C复合材料。利用该复合材料组装的锂电池和钠电池,可以同时实现高容量、高倍率、高首次库伦效率和高稳定性。(The invention discloses a lithium/sodium ion battery cathode material nickel selenide/carbon composite material and a preparation method thereof. The method comprises the following steps: 1) putting nickel chloride hexahydrate, citric acid and urea into a mixed solution of ethanol and water together, heating in a water bath, stirring, and drying to obtain a nickel salt precursor; 2) removing the nickel salt precursorCarbonizing the organic matter at high temperature to obtain the nickel/carbon composite material; 3) grinding a nickel/carbon composite material into nickel/carbon powder, placing the nickel/carbon powder into water, performing ultrasonic dispersion to obtain a solution A, adding selenium powder into the water, performing magnetic stirring, and adding sodium borohydride to obtain a solution B; 4) adding the solution B into the solution A, carrying out hydrothermal reaction, cooling, filtering, washing and drying to obtain Ni 3 Se 4 a/C composite material. The lithium battery and the sodium battery assembled by the composite material can simultaneously realize high capacity, high multiplying power, high first coulombic efficiency and high stability.)

1. Lithium/sodium ion battery negative electrode material Ni₃Se₄The preparation method of the/C composite material is characterized by comprising the following steps: which comprises the following steps:

1) putting nickel chloride hexahydrate, citric acid and urea into a mixed solution of ethanol and water together to obtain a mixed solution, heating and stirring the mixed solution in a water bath to obtain gel, and putting the gel into an oven to dry to obtain a nickel salt precursor;

2) putting the nickel salt precursor into a tube furnace, removing organic matters, then carrying out high-temperature carbonization treatment, and cooling to room temperature to obtain a nickel/carbon composite material;

3) grinding a nickel/carbon composite material into nickel/carbon powder, placing the nickel/carbon powder into water, performing ultrasonic dispersion to obtain a solution A, adding selenium powder into the water, performing magnetic stirring, and adding sodium borohydride during stirring to obtain a solution B;

4) adding the solution B into the solution A, transferring the solution B into a high-pressure reaction kettle with a polytetrafluoroethylene lining, performing hydrothermal reaction, cooling to room temperature, filtering to obtain powder, washing the powder, and drying to obtain Ni₃Se₄a/C composite material.

2. The negative electrode material Ni of claim 1 for lithium/sodium ion battery₃Se₄The preparation method of the/C composite material is characterized by comprising the following steps: the mass ratio of the nickel chloride hexahydrate, the citric acid and the urea in the step 1) is 0.1-0.6: 0.5-2: 3-8.

3. The negative electrode material Ni of claim 1 for lithium/sodium ion battery₃Se₄The preparation method of the/C composite material is characterized by comprising the following steps: in the step 2), the organic matter removing condition is to heat the mixture to 200-400 ℃ at a heating rate of 3-10 ℃/min in a nitrogen environment and to keep the temperature for 1-3 h.

4. The negative electrode material Ni of claim 1 for lithium/sodium ion battery₃Se₄The preparation method of the/C composite material is characterized by comprising the following steps: in the step 2), the carbonization treatment condition is that the temperature is increased to 700-900 ℃ at the heating rate of 3-10 ℃/min and is kept for 4-6h under the nitrogen environment.

5. The negative electrode material Ni of claim 1 for lithium/sodium ion battery₃Se₄The preparation method of the/C composite material is characterized by comprising the following steps: in the step 3), the dosage ratio of the nickel/carbon powder to the water is 0.06g to 5-15ml, and the dosage ratio of the selenium powder, the sodium borohydride and the water is 0.16g to 0.11-0.12g to 5-15 ml.

6. The negative electrode material Ni of claim 1 for lithium/sodium ion battery₃Se₄The preparation method of the/C composite material is characterized by comprising the following steps: in the step 4), the dosage ratio of the solution A to the solution B meets the following condition, and the nickel/carbon powder in the solution A and the nickel/carbon powder in the solution BThe mass ratio of the selenium powder to the sodium borohydride is 6:16: 11.

7. The negative electrode material Ni of claim 1 for lithium/sodium ion battery₃Se₄The preparation method of the/C composite material is characterized by comprising the following steps: the hydrothermal reaction in the step 4) is carried out for 12-13h at the temperature of 150-170 ℃.

8. The negative electrode material Ni of claim 1 for lithium/sodium ion battery₃Se₄The preparation method of the/C composite material is characterized by comprising the following steps: and the washing in the step 4) is centrifugal washing for 3-5 times by using absolute ethyl alcohol and deionized water.

9. Ni obtained by the production method according to any one of claims 1 to 8₃Se₄a/C composite material.

10. Use of Ni as defined in claim 9₃Se₄The method for preparing the battery cathode by the/C composite material is characterized by comprising the following steps: which comprises the following steps:

1) mixing Ni₃Se₄Mixing the/C composite material, acetylene black and sodium alginate to obtain a mixture, wherein the Ni is₃Se₄The mass ratio of the/C composite material to the acetylene black to the sodium alginate is 5-9: 0.5-2: 0.5-1;

2) and adding water into the mixture, stirring to obtain slurry, uniformly coating the slurry on a copper foil, transferring to a vacuum oven for drying, and preparing into an electrode plate by using a sheet punching machine to obtain the battery cathode.

Technical Field

The invention relates to a preparation method of a battery cathode material, in particular to a lithium/sodium ion battery cathode material nickel selenide/carbon composite material and a preparation method thereof.

Background

With the reduction of fossil fuels and the generation of climate change and other problems, sustainable development and environmental protection become important topics for people, and more researchers actively develop efficient and clean new energy. Since the beginning of the 20 th century 90 s, japanese sony corporation has successfully developed lithium ion batteries, which have light weight, high operating voltage, high energy density, and long cycle life, have become the dominant force in the secondary energy market, and are widely used in the energy storage fields of portable electronic products, electric vehicles, electric automobiles, and the like. The rise of the emerging technology industries such as electric automobiles brings a wider platform for lithium ion batteries, and meanwhile, lithium is trapped in the resource shortage dilemma. The sodium element has rich resource, low price, good safety performance and similar physical and chemical properties with lithium ions, and if the sodium can replace the lithium element to enter the army energy storage field, the situation of shortage of the lithium element resource can be solved to a great extent.

The negative electrode material, which is an important component of a lithium/sodium battery, is a major contributor to battery capacity. At present, carbon-based materials, transition metal oxides, metals and alloys thereof and the like are common cathode materials of lithium ion batteries. Because the ionic radius of sodium ions is larger than that of lithium ions, some common lithium battery negative electrode materials cannot meet the reversible deintercalation of the sodium ions. The negative electrode materials of the sodium ion battery researched at present mainly comprise: a carbon-based negative electrode, a titanium-based oxide negative electrode, an alloy negative electrode, a transition metal sulfide negative electrode, and a transition metal phosphate negative electrode. The transition metal chalcogenide is considered as a potential sodium electric negative electrode material due to high theoretical capacity, large interlayer spacing and good conductivity. Among them, the outstanding appearance of selenide has gradually become one of the popular research directions for the negative electrode material. Due to the wide variety of selenides, NiSe and Ni are common_0.85Se、Ni₃Se₄And NiSe₂In order to better improve the electrochemical performance of the selenide, how to controllably prepare the selenide with a specific composition becomes a technical problem which is urgently needed to be solved at present.

Disclosure of Invention

In order to solve the technical problems, the invention provides a lithium/sodium ion battery cathode material nickel selenide/carbon composite material and a preparation method thereof, and the method can effectively and controllably prepare Ni₃Se₄and/C, improving the electrochemical performance of the negative electrode material.

In order to achieve the purpose, the invention adopts the following technical scheme:

lithium/sodium ion battery negative electrode material Ni₃Se₄The preparation method of the/C composite material comprises the following steps:

1) putting nickel chloride hexahydrate, citric acid and urea into a mixed solution of ethanol and distilled water together to obtain a mixed solution, heating and stirring the mixed solution in a water bath to obtain green gel, and putting the gel into an oven for drying to obtain a nano flaky nickel salt precursor;

2) putting the nickel salt precursor into a tube furnace, removing organic matters, then carrying out high-temperature carbonization treatment, and cooling to room temperature to obtain a nickel/carbon composite material;

3) grinding a nickel/carbon composite material into nickel/carbon powder, placing the nickel/carbon powder into distilled water, performing ultrasonic dispersion to obtain a solution A, adding selenium powder into the distilled water, performing magnetic stirring, and adding sodium borohydride during stirring to obtain a solution B;

4) adding the solution B into the solution A, transferring the solution B into a high-pressure reaction kettle with a polytetrafluoroethylene lining, performing hydrothermal reaction, cooling to room temperature, filtering to obtain black powder, washing the black powder, and drying in an oven to obtain Ni₃Se₄a/C composite material.

The mass ratio of the nickel chloride hexahydrate, the citric acid and the urea in the step 1) is 0.1-0.6: 0.5-2: 3-8.

In the step 2), the organic matter removing condition is to heat the mixture to 200-400 ℃ at a heating rate of 3-10 ℃/min in a nitrogen environment and to keep the temperature for 1-3 h.

In the step 2), the carbonization treatment condition is that the temperature is increased to 700-900 ℃ at the heating rate of 3-10 ℃/min and is kept for 4-6h under the nitrogen environment.

In the step 3), the dosage ratio of the nickel/carbon powder to the distilled water is 0.06g to 5-15ml, and the dosage ratio of the selenium powder, the sodium borohydride and the distilled water is 0.16g to 0.11-0.12g to 5-15 ml.

In the step 4), the dosage ratio of the solution A to the solution B meets the following condition, and the mass ratio of the nickel/carbon powder in the solution A to the selenium powder and the sodium borohydride in the solution B is 6:16: 11.

The hydrothermal reaction in the step 4) is carried out for 12-13h at the temperature of 150-170 ℃.

And the washing in the step 4) is centrifugal washing for 3-5 times by using absolute ethyl alcohol and deionized water.

Using said Ni₃Se₄The method for preparing the battery cathode by the/C composite material comprises the following steps:

1) mixing Ni₃Se₄Mixing the/C composite material, acetylene black and sodium alginate to obtain a mixture, wherein the Ni is₃Se₄The mass ratio of the/C composite material to the acetylene black to the sodium alginate is 5-9: 0.5-2: 0.5-1;

2) and adding water into the mixture, stirring to obtain slurry, uniformly coating the slurry on a copper foil, transferring to a vacuum oven for drying, and preparing into an electrode plate by using a sheet punching machine to obtain the battery cathode.

Ni in step 1)₃Se₄The mass ratio of the/C composite material to the acetylene black to the sodium alginate is 7:2: 1.

The temperature of the vacuum oven in step 2) was selected to be 80 ℃.

The invention adopts the method to prepare i₃Se₄a/C composite material using Ni₃Se₄The negative electrode of the lithium/sodium battery is prepared from the/C composite material, the conductivity of the negative electrode is improved by using the nano sheet, and controllable preparation can be realized.

According to the invention, a hydrothermal method is adopted to prepare the nickel-based selenide, firstly, a nickel salt precursor with uniform nanosheet morphology is prepared through hydrothermal reaction, in-situ compounding of carbon is realized at the precursor stage, the precursor is selenized on the premise of keeping uniform and compact nanosheet morphology undamaged, and the preparation method is simple, safe, efficient and controllable.

The invention has the beneficial effects that: the lithium battery and the sodium battery assembled by the composite material realize high capacity, high multiplying power, high first coulombic efficiency and high stability. From Ni₃Se₄Lithium cell assembled by using/C composite material as negative electrode and having current density of 0.2A g^-1At this time, the initial discharge/charge capacity was 942.7/589.1 mAh g^-1And 586.2 mAh g can be maintained after 100 cycles^-1The capacity retention rate of (2) is 94.4%; current Density 5A g^-1The discharge capacity can be as high as 589.1 mAh g^-1. When used as a sodium-electric cathode, the current density is 0.2A g^-1Initial discharge/charge capacity at 497.4/368.7 mAh g^-1After 100 cycles, the discharge capacity was 167.9 mAh g-1, and the capacity retention rate was 42.8%.

Drawings

In FIG. 1, (a) is attached to Ni₃Se₄X-ray diffraction pattern of/C composite material, wherein (b) the figure is Ni obtained under different nickel sources₃Se₄X-ray diffraction pattern of the/C composite material;

in FIG. 2, (a) and (b) are scanning electron micrographs of the Ni/C composite material of the present invention, and (C) and (d) are Ni₃Se₄Scanning electron microscope images of the/C composite material;

FIG. 3 (a) is a transmission electron microscope and a size distribution diagram of the Ni/C composite material of the present invention, and (b) is Ni of the present invention₃Se₄Transmission electron microscope and size distribution diagram of the/C composite material;

in FIG. 4, (a) is a drawing showing Ni in the present invention₃Se₄The charge and discharge performance curve diagram of lithium battery of the/C composite material is shown in the figure (b) of the invention₃Se₄The cycle performance and rate performance curve diagram of lithium battery of the/C composite material is shown in the figure (C) of the invention₃Se₄The lithium battery rate performance curve diagram of the/C composite material.

In FIG. 5, (a) is a drawing showing Ni in the present invention₃Se₄The charge and discharge performance curve diagram of sodium battery of the/C composite material is shown in the figure (b) of the invention₃Se₄The cycle performance and rate performance curve diagram of sodium battery of the/C composite material is shown in the figure, wherein (C) the figure is Ni in the invention₃Se₄The sodium battery rate performance curve diagram of the/C composite material.

Detailed Description

Lithium/sodium ion battery negative electrode material Ni₃Se₄The preparation method of the/C composite material comprises the following steps:

1) putting nickel chloride hexahydrate, citric acid and urea into a mixed solution of ethanol and distilled water together to obtain a mixed solution, heating and stirring the mixed solution in a water bath to obtain green gel, and putting the gel into an oven for drying to obtain a nano flaky nickel salt precursor;

the mass ratio of the nickel chloride hexahydrate to the citric acid to the urea is 0.1-0.6: 0.5-2: 3-8;

2) putting the nickel salt precursor into a tube furnace, heating to 200-400 ℃ at the heating rate of 3-10 ℃/min in the nitrogen environment, and carrying out heat treatment for 1-3h to remove organic matters;

3) heating the product obtained in the step 2) to 700-900 ℃ at the heating rate of 3-10 ℃/min in the nitrogen environment, preserving the heat for 4-6h for heat treatment, and then cooling to room temperature to obtain the nickel/carbon composite material;

4) grinding the nickel/carbon composite material into nickel/carbon powder, placing the nickel/carbon powder into distilled water, and performing ultrasonic dispersion to obtain a solution A, wherein the dosage ratio of the nickel/carbon powder to the distilled water is 0.06g: 5-15 ml;

adding selenium powder into distilled water, magnetically stirring, and adding sodium borohydride during stirring to obtain a solution B, wherein the dosage ratio of the selenium powder to the sodium borohydride to the distilled water is 0.16g to 0.11-0.12g to 5-15 ml;

5) adding the solution B into the solution A, transferring the solution B into a high-pressure reaction kettle with polytetrafluoroethylene as a lining, carrying out hydrothermal reaction at the temperature of 150-170 ℃ for 12-13h, cooling to room temperature, filtering to obtain black powder, and mixing the black powderCentrifugally washing with anhydrous ethanol and deionized water for 3-5 times, and drying in oven to obtain Ni₃Se₄a/C composite material.

Using said Ni₃Se₄The method for preparing the battery cathode by the/C composite material comprises the following steps:

1) mixing Ni₃Se₄Mixing the/C composite material, acetylene black and sodium alginate to obtain a mixture, wherein the Ni is₃Se₄The mass ratio of the/C composite material to the acetylene black to the sodium alginate is 5-9: 0.5-2: 0.5-1, preferably 7:2: 1;

2) and adding water into the mixture, stirring to obtain slurry, uniformly coating the slurry on a copper foil, transferring the copper foil to a vacuum oven, drying at 80 ℃, and preparing into an electrode plate by using a sheet punching machine to obtain the battery cathode.

The present invention will be described in further detail with reference to specific examples.