阅读说明：本技术 一种红磷电极的制备方法 (Preparation method of red phosphorus electrode ) 是由 李仕琦 冷丹 汶飞 邓天松 李丽丽 于 2021-07-06 设计创作，主要内容包括：本发明公开了一种红磷电极的制备方法,主要采用光照苯膦酰二氯使得苯膦酰二氯分解的方式制备红磷电极。采用本发明的技术方案,可以很好地将苯膦酰二氯与宿主材料混合,最终得到纳米红磷与宿主材料均匀混合的红磷电极,从而提高红磷电极的电子导电性,抑制红磷电极充放电过程中的体积膨胀,提高红磷电极的库伦效率,改善红磷电极的循环稳定性。(The invention discloses a preparation method of a red phosphorus electrode, which mainly adopts a mode of irradiating phenylphosphonic dichloride to decompose the phenylphosphonic dichloride to prepare the red phosphorus electrode. By adopting the technical scheme of the invention, the phenylphosphonic dichloride and the host material can be well mixed, and the red phosphorus electrode with the nano red phosphorus and the host material uniformly mixed is finally obtained, so that the electronic conductivity of the red phosphorus electrode is improved, the volume expansion of the red phosphorus electrode in the charging and discharging processes is inhibited, the coulombic efficiency of the red phosphorus electrode is improved, and the cycle stability of the red phosphorus electrode is improved.)

1. A preparation method of a red phosphorus electrode is characterized by comprising the following steps:

step S1, dissolving phenylphosphonic dichloride in carbon tetrachloride to obtain a carbon tetrachloride solution of the phenylphosphonic dichloride;

step S2, uniformly mixing a carbon material and a carbon tetrachloride solution of phenylphosphonic dichloride;

and step S3, irradiating the carbon tetrachloride solution of the phenylphosphonic dichloride to decompose the phenylphosphonic dichloride to obtain the red phosphorus electrode.

2. The method of manufacturing a red phosphorus electrode according to claim 1, wherein the concentration of the phenylphosphonic dichloride in step S1 is 3 mol/L.

3. The method of manufacturing a red phosphorus electrode according to claim 1, wherein in step S2, the mass ratio of the carbon material to the phenylphosphonic dichloride is 1: 10.

4. The method of claim 1, wherein in step S3, the wavelength of the light source is 365 nm.

Technical Field

The invention belongs to the technical field of lithium ion batteries, and particularly relates to a preparation method of a red phosphorus electrode.

Background

Because renewable energy has the characteristic of instability, the renewable energy needs to be stored in order to be better utilized. Therefore, charging and discharging the battery will function sufficiently in this field. However, the current lithium ion batteries have low specific energy, which limits their application in this field. In order to increase the specific energy of lithium ion batteries, it is necessary to develop electrode materials having high specific capacity. Red phosphorus has a specific capacity of 2600mAh/g, so that red phosphorus is considered to be an ideal electrode material for next-generation lithium ion batteries. In addition, the red phosphorus has the characteristics of environmental friendliness, abundant raw materials, low cost and the like.

However, the commercialization of red phosphorus electrodes still faces some problems, including poor electron conductivity of red phosphorus and large volume change during the charge and discharge of red phosphorus. In recent years, researchers have made many studies on how to improve the electron conductivity of a red phosphorus electrode and suppress the volume change of the red phosphorus electrode during the charge and discharge processes. The most effective method is to mix red phosphorus with carbon materials, such as carbon nanotubes, mesoporous carbon, carbon spheres, etc., by mechanical ball milling or sublimation condensation, and to compound or coat the carbon materials with red phosphorus. However, red phosphorus has the characteristic of high melting point and is very easy to be transformed into dangerous white phosphorus at high temperature, and the red phosphorus and a carbon material cannot be well mixed by the traditional method, so that the coulomb efficiency of a red phosphorus electrode is low, and the cycle stability is poor. Therefore, a more efficient method for preparing red phosphorus electrodes is also sought.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides a preparation method of a red phosphorus electrode. The red phosphorus electrode is prepared mainly by adopting a mode of irradiating the phenylphosphonic dichloride to decompose the phenylphosphonic dichloride. By adopting the technical scheme of the invention, the phenylphosphonic dichloride can be well mixed with the host material, and the phenylphosphonic dichloride is decomposed by illuminating the phenylphosphonic dichloride, so that the red phosphorus electrode with the red phosphorus and the host material uniformly mixed is finally obtained, thereby improving the electronic conductivity of the red phosphorus electrode, inhibiting the volume expansion of the red phosphorus electrode, improving the coulombic efficiency of the red phosphorus electrode and improving the cycle stability of the red phosphorus electrode.

In order to solve the problems in the prior art, the invention provides a preparation method of a red phosphorus electrode, which comprises the following steps:

step S1, dissolving phenylphosphonic dichloride in carbon tetrachloride to obtain a carbon tetrachloride solution of the phenylphosphonic dichloride;

step S2, uniformly mixing a carbon material and a carbon tetrachloride solution of phenylphosphonic dichloride;

and step S3, irradiating the carbon tetrachloride solution of the phenylphosphonic dichloride to decompose the phenylphosphonic dichloride to obtain the red phosphorus electrode.

As a preferable embodiment, in step S1, the concentration of phenylphosphonyl dichloride is 3 mol/L.

Preferably, in step S2, the mass ratio of the carbon material to the phenylphosphonyl dichloride is 1: 10.

Preferably, in step S3, the wavelength of the light source is 365 nm.

Compared with the prior art, the invention has the following beneficial effects:

(1) the method provided by the invention is simple in process and easy to realize.

(2) The phenylphosphonic dichloride and the carbon material are effectively and uniformly mixed, and the red phosphorus electrode material with red phosphorus uniformly dispersed in the carbon material is obtained after illumination.

(3) The specific capacity of the red phosphorus electrode is improved, and the cycling stability of the red phosphorus electrode is enhanced.

Drawings

Fig. 1 is a test chart of instantiation 1 of the present invention, in which (a) is a cycle capacity curve of a red phosphorus electrode prepared by the method of example 1 of the present invention at a charge and discharge current of 0.2C and (b) is a cycle capacity curve of a red phosphorus electrode prepared by a conventional ball milling method at a charge and discharge current of 0.2C;

the following specific embodiments will further illustrate the invention in conjunction with the above-described figures.

Detailed Description

In order to better explain the process and scheme of the present invention, the following invention is further described with reference to the accompanying drawings and examples. The specific embodiments described herein are merely illustrative of the invention and do not delimit the invention.

The invention provides a preparation method of a novel red phosphorus electrode, which comprises the following steps:

step S1, dissolving phenylphosphonic dichloride in carbon tetrachloride to obtain a carbon tetrachloride solution of the phenylphosphonic dichloride;

step S2, uniformly mixing a carbon material and a carbon tetrachloride solution of phenylphosphonic dichloride;

and step S3, irradiating the carbon tetrachloride solution of the phenylphosphonic dichloride to decompose the phenylphosphonic dichloride to obtain the red phosphorus electrode.

In the technical scheme, the carbon material and the phenylphosphonic dichloride are uniformly mixed, and the phenylphosphonic dichloride is decomposed by illumination to obtain the red phosphorus electrode in which the red phosphorus is uniformly dispersed in the carbon material, so that the electronic conductivity of the red phosphorus electrode is improved, the volume expansion of the red phosphorus electrode in the charging and discharging processes is inhibited, and the cycle stability of the red phosphorus electrode is improved.

EXAMPLE 1

Dissolving phenylphosphonic dichloride in carbon tetrachloride to obtain a 3M/L phenylphosphonic dichloride carbon tetrachloride solution; mixing porous carbon with a carbon tetrachloride solution of phenylphosphonic dichloride, wherein the mass ratio of the carbon material to the phenylphosphonic dichloride is 1: 10; and irradiating the mixture of the carbon material and the phenylphosphonic dichloride by using light with the wavelength of 365nm to obtain the composite material in which the red phosphorus is uniformly dispersed in the carbon material.

Instantiation 2

Dissolving phenylphosphonic dichloride in carbon tetrachloride to obtain a 5M/L phenylphosphonic dichloride carbon tetrachloride solution; mixing porous carbon with a carbon tetrachloride solution of phenylphosphonic dichloride, wherein the mass ratio of the carbon material to the phenylphosphonic dichloride is 1: 8; and irradiating the mixture of the carbon material and the phenylphosphonic dichloride by using light with the wavelength of 365nm to obtain the composite material in which the red phosphorus is uniformly dispersed in the carbon material.

Instantiation 3

Dissolving phenylphosphonic dichloride in carbon tetrachloride to obtain a 5M/L phenylphosphonic dichloride carbon tetrachloride solution; mixing porous carbon with a carbon tetrachloride solution of phenylphosphonic dichloride, wherein the mass ratio of the carbon material to the phenylphosphonic dichloride is 1: 8; and irradiating the mixture of the carbon material and the phenylphosphonic dichloride by using light with the wavelength of 254nm to obtain the composite material in which the red phosphorus is uniformly dispersed in the carbon material.

Instantiation 4

Dissolving phenylphosphonic dichloride in carbon tetrachloride to obtain a 1M/L phenylphosphonic dichloride carbon tetrachloride solution; mixing porous carbon with a carbon tetrachloride solution of phenylphosphonic dichloride, wherein the mass ratio of the carbon material to the phenylphosphonic dichloride is 1: 4; and irradiating the mixture of the carbon material and the phenylphosphonic dichloride by using light with the wavelength of 254nm to obtain the composite material in which the red phosphorus is uniformly dispersed in the carbon material.

Fig. 1(a) is a cyclic capacity curve of the red phosphorus electrode obtained in instantiation 1 of the present invention under a charge and discharge current of 0.2C, the specific capacity of the red phosphorus electrode can reach 1863mAh/g, and the capacity of the red phosphorus electrode still remains 1752mAh/g after 100 cycles. Fig. 1(b) shows the electrochemical performance of a sulfur electrode prepared by a conventional method.

Further, the performance test is carried out on the method. The specific test process is as follows: a half-cell test red phosphorus electrode is adopted, a negative electrode is a lithium sheet, Celgard2325 is used as a diaphragm, LiPF6 with 1M electrolyte is dissolved in a solution of ethylene carbonate, diethyl carbonate and dimethyl carbonate, and the battery is assembled by using an LIR2032 coin-shaped battery case in a glove box which is filled with argon gas for protection and has the humidity and oxygen concentration lower than 1 ppm. In the charge and discharge test system, the charge and discharge test voltage is 1.7V-2.8V.

According to the analysis, the red phosphorus in the red phosphorus electrode prepared by the method can be uniformly dispersed in the electrode, so that the electronic conductivity of the red phosphorus electrode is effectively improved, and the volume change of the red phosphorus electrode in the charging and discharging processes is inhibited. The specific capacity of the obtained red phosphorus electrode can reach 1863mAh/g, and the capacity can still maintain 1752mAh/g after the red phosphorus electrode is cycled for 100 times. The method effectively improves the cycle stability of the red phosphorus electrode.

The above description of the embodiments is only intended to facilitate the understanding of the method of the invention and its core idea. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.