阅读说明：本技术 一种液相沉淀法合成单质铋纳米片负载碳布复合材料制备方法 (Preparation method for synthesizing elemental bismuth nanosheet loaded carbon cloth composite material by liquid-phase precipitation method ) 是由 罗志高 李兰艳 李金烨 史恒瑞 于 2021-11-02 设计创作，主要内容包括：本发明公开了一种沉淀法合成单质铋纳米片负载碳布钠离子电池负极材料的制备方法,将铋源,表面活性剂和溶于水中陈化一定时间后,搅拌,同时往铋源中滴加入pH调节剂,加入碳布,一定温度下反应1到2个小时,离心分离,洗涤干燥得到铋纳米片前驱体。进一步热处理可以得到单质铋纳米片负载碳布。该制备方法的工艺简单、易于操作,流程短,产品质量稳定。用作钠离子电池负极显示出优异的电化学性质,包括较高的比容量和优异的长循环性能。(The invention discloses a preparation method of a bismuth nanosheet loaded carbon cloth sodium-ion battery cathode material synthesized by a precipitation method. And further carrying out heat treatment to obtain the elemental bismuth nanosheet loaded carbon cloth. The preparation method has the advantages of simple process, easy operation, short flow and stable product quality. The lithium ion battery cathode shows excellent electrochemical properties including higher specific capacity and excellent long cycle performance when used as a sodium ion battery cathode.)

1. A preparation method of an elemental bismuth nanosheet material comprises the following steps: (1) a quantity of bismuth source, surfactant, was dissolved in deionized water and then aged to precipitate. (2) Slowly dropwise adding potassium hydroxide under the stirring condition. (3) After the dropwise addition is finished, adding carbon cloth, and continuously reacting for a period of time at a certain temperature. (4) The obtained white precipitate loaded carbon cloth was washed three times with deionized water and ethanol, respectively, and vacuum-dried at 80 ℃ for 8 hours. Obtaining the bismuth nanosheet precursor loaded carbon cloth, and further processing the bismuth nanosheet precursor to obtain the simple substance bismuth nanosheet.

2. The method of claim 1, wherein the reactant used for preparing the elemental bismuth nanosheets is one or more of bismuth nitrate pentahydrate (Bi (NO3) 35H 2O), sodium bismuthate (NaBiO3), bismuth chloride (BiCl3), and bismuth citrate (C6H5BiO 7).

3. The method according to claim 1, wherein the surfactant is cetyltrimethyl amine, polyethylene glycol, polyvinylpyrrolidone, etc., and the concentration of the surfactant is 0.1 to 1g/L

4. The method according to claim 1, wherein the pH regulator is selected from the group consisting of potassium hydroxide, sodium hydroxide, etc., and ammonia water, and the pH is adjusted to 10 to 13 by using the pH regulator.

5. The method according to claim 1, wherein the temperature during the reaction is 20 to 80 ℃ and the reaction time is 1 to 3 hours.

6. The carbon cloth of claim 1, which is a commercial conductive carbon cloth.

7. The method according to claim 1, wherein the bismuth nanosheet precursor-loaded carbon cloth is further treated to be calcined at 200-400 ℃ for 2-6 hours in a reducing atmosphere.

8. The method of claim 1, wherein the reducing gas is argon or nitrogen and hydrogen.

Technical Field

The invention relates to the technical field of nano material synthesis and electrochemical technology application, in particular to a preparation method for synthesizing a simple substance bismuth nanosheet material by a liquid-phase precipitation method.

Background

Sodium ion batteries have entered a period of rapid development because of the abundant resource reserves of sodium on earth, which is almost ubiquitous on earth, relatively concentrated in distribution on earth unlike lithium, and the relatively low price of sodium. Most importantly, sodium and lithium are in the same main group, and their chemical properties are similar, so the basic principle applied to batteries is the same. The radius of sodium ions is larger than that of lithium ions, and the graphite which is suitable for the negative electrode material of the lithium ion battery can not effectively insert the sodium ions, so that the negative electrode material of the sodium ion battery is not commercialized very successfully at present. Meanwhile, most of the research on the positive electrode material of the sodium-ion battery is based on the lithium-ion battery, and the performance of the positive electrode material used for the sodium-ion battery system does not reach the real practical level. In summary, the current sodium ion battery has problems of unsatisfactory cycle life, unstable high current charging and discharging performance, etc. [13 ]. Therefore, the negative electrode material of the sodium-ion battery becomes a depression restricting the development of the sodium-ion battery, and the research and development of the negative electrode material of the sodium-ion battery with high capacity, good safety, low cost and excellent electrochemical performance is urgent.

Bismuth-based materials are one of the new sodium ion battery negative electrode materials that have begun to be of interest. Bismuth metal has some unique properties such as a low melting point, an increase in volume upon solidification, etc., and it is also the least thermally conductive metal. Simple substance bismuth is widely concerned due to the characteristics of stability, no toxicity, low discharge platform and the like. However, the existing preparation method of the Bi nano material is very limited, and a chinese patent (CN108400292A) invented a mechanical stripping and normal temperature reduction method to prepare the elemental bismuth nanosheet with a two-dimensional structure. The advantage of high specific surface area is fully utilized, and the material has good electrochemical performance when being used as a negative electrode material of a sodium ion battery. The preparation process of the bismuth nanosheet is simplified through a simple precipitation method and a thermal reduction method.

Disclosure of Invention

The invention aims to provide a preparation method for synthesizing an elemental bismuth nanosheet loaded carbon cloth composite material by a liquid-phase precipitation method, and the simple liquid-phase precipitation method effectively saves the synthesis time and the manufacturing cost.

The technical scheme of the invention is as follows: the elemental bismuth nanosheet loaded carbon cloth composite material adopts a liquid-phase precipitation method and a subsequent thermal reduction method under the synergistic action of a surfactant and a pH regulator. The method comprises the following specific steps:

(1) dissolving a certain amount of surfactant in deionized water, adding a certain amount of bismuth nitrate pentahydrate or bismuth chloride, dissolving, and aging for half an hour. The concentration of bismuth nitrate or bismuth chloride is preferably 0.001mol/L, the concentration of surfactant is preferably 0.5g/L,

(2) slowly dripping a pH regulator under the stirring condition. The pH value of the system is preferably adjusted to be 12 by using a pH regulator.

(3) After the dropwise addition is finished, the reaction is continued for a period of time at a certain temperature. The obtained white precipitate loaded carbon cloth was washed three times with deionized water and ethanol, respectively, and vacuum-dried at 80 ℃ for 8 hours. The reaction temperature is preferably 50 ℃ and the reaction time is preferably 6 hours.

(4) Further calcining for 2-4 hours in a reducing atmosphere at 200-400 ℃.

In the above preparation method, preferably, the surfactant is one or more of cetyltrimethyl amine, polyethylene glycol, and polyvinylpyrrolidone.

In the above preparation method, preferably, the pH adjuster is potassium hydroxide, sodium hydroxide, or the like, and ammonia water.

In the preparation method, preferably, the elemental bismuth nanosheet loaded carbon cloth is further processed to 200 ℃, and is calcined for 2 hours in an argon and hydrogen mixed atmosphere.

Drawings

Fig. 1 is an XRD pattern of the elemental bismuth nanosheet-supported carbon cloth material obtained in example 1 of the present invention.

Fig. 2 is an SEM image of elemental bismuth nanosheet precursor-supported carbon cloth obtained in example 1 of the present invention.

Fig. 3 is an SEM image of the elemental bismuth nanosheet-supported carbon cloth material obtained in embodiment 2 of the present invention.

FIG. 4 is a TEM image of elemental bismuth nanosheets obtained in example 1 of the present invention

Fig. 5 is an electrical property curve diagram of the elemental bismuth nanosheet-supported carbon cloth material obtained in embodiment 1 of the present invention.

Detailed Description

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

Example 1

The preparation method for synthesizing the elemental bismuth nanosheet loaded carbon cloth material by the precipitation method comprises the following steps:

0.05g of polyvinylpyrrolidone (PVP) is dissolved in deionized water, 1mmol of bismuth nitrate pentahydrate is added, and the mixture is aged for half an hour after dissolution. Slowly dropwise adding 0.1mol/L potassium hydroxide solution under the stirring condition. The pH value of the system is adjusted to 12. After the addition, the reaction was continued at 80 ℃ for 2 hours. The obtained white precipitate loaded carbon cloth was washed three times with deionized water and ethanol, respectively, and vacuum-dried at 80 ℃ for 8 hours. The calcination was further carried out at 400 ℃ for 2 hours in a mixed atmosphere of hydrogen and argon.

An XRD spectrogram of the elemental bismuth nanosheet supported carbon cloth material prepared in the method example 1 is shown in figure 1. The results matched the standard curve of the standard card (JCPDS card NO. 44-1246).

An SEM image of the elemental bismuth nanosheet precursor-loaded carbon cloth material prepared in the embodiment 1 of the method is shown in FIG. 2, and the nanosheets are uniformly distributed on the carbon cloth fibers.

A TEM image of the elemental bismuth nanosheets prepared in example 1 of the method is shown in fig. 4.

The electrochemical performance of the elemental bismuth nanosheet loaded carbon cloth material prepared in the embodiment 1 of the method is shown in fig. 5, and the material obtains the specific first discharge capacity of 700mAh g-1 at the current density of 100 mAg-1.

Example 2

0.05g of polyethylene glycol is dissolved in deionized water, 2mmol of bismuth chloride is added, and the mixture is aged for half an hour after dissolution. Slowly dropwise adding 0.1mol/L potassium hydroxide solution under the stirring condition. The pH value of the system is adjusted to 12. After the addition, the reaction was continued at 80 ℃ for 2 hours. The obtained white precipitate loaded carbon cloth was washed three times with deionized water and ethanol, respectively, and vacuum-dried at 80 ℃ for 8 hours. The calcination was further carried out at 400 ℃ for 2 hours in a mixed atmosphere of hydrogen and argon.

An SEM spectrogram of the elemental bismuth nanosheet supported carbon cloth material prepared in the method example 2 is shown in fig. 3.