阅读说明：本技术 一种有效抑制锂硫电池穿梭效应的方法 (Method for effectively inhibiting shuttle effect of lithium-sulfur battery ) 是由 李仕琦 冷丹 汶飞 邓天松 李丽丽 于 2021-06-28 设计创作，主要内容包括：本发明公开了一种有效抑制锂硫电池穿梭效应的方法,采用将锂硫电池固定在匀速转动的圆盘边沿的方法,其中锂硫电池的负极距离圆心较近,相应的正极距离圆心较远,随着圆盘的转动产生的离心力可以起到抑制锂硫电池穿梭效应的作用。采用本发明的技术方案,可以很好地阻止正极聚硫锂向负极扩散,从而抑制锂硫电池的穿梭效应,提高锂硫电池的库伦效率,提升锂硫电池的循环稳定性。(The invention discloses a method for effectively inhibiting shuttle effect of a lithium-sulfur battery, which adopts a method for fixing the lithium-sulfur battery at the edge of a disk rotating at a constant speed, wherein the cathode of the lithium-sulfur battery is closer to the center of a circle, the corresponding anode is farther from the center of the circle, and the centrifugal force generated along with the rotation of the disk can play a role in inhibiting the shuttle effect of the lithium-sulfur battery. By adopting the technical scheme of the invention, the positive polysulfide lithium can be well prevented from diffusing to the negative electrode, so that the shuttle effect of the lithium-sulfur battery is inhibited, the coulombic efficiency of the lithium-sulfur battery is improved, and the cycle stability of the lithium-sulfur battery is improved.)

1. A method for effectively inhibiting shuttling effects in a lithium sulfur battery, comprising the steps of:

step S1, fixing the lithium-sulfur battery at the circumferential edge of the disk capable of rotating at a constant speed;

step S2, making the anode of the lithium sulfur battery far from the circle center and the corresponding cathode of the battery near to the circle center;

and step S3, enabling the disc to rotate at a constant speed, enabling the lithium sulfur battery fixed on the disc to be subjected to centrifugal force generated by the rotation of the disc, and enabling the lithium sulfur battery subjected to the centrifugal force to effectively inhibit the shuttling effect.

2. The method for effectively suppressing shuttling effect of lithium sulfur battery as claimed in claim 1, wherein in step S1, the radius of the disc is 20-50 cm.

3. The method for effectively suppressing shuttling effect of lithium sulfur battery as claimed in claim 1, wherein in step S3, the rotation speed of the disc is 300-1000 r/min.

4. The method of claim 2, wherein the radius of the disk is 30 cm.

5. The method for effectively suppressing shuttling effect of a lithium sulfur battery as recited in claim 3 wherein the rotation speed of the disk is 600 r/min.

Technical Field

The invention belongs to the technical field of lithium-sulfur batteries, and particularly relates to a method for effectively inhibiting shuttle effect of a lithium-sulfur battery.

Background

In order to solve the energy crisis and the environmental pollution problem, the development of renewable energy and novel energy is gradually being emphasized by people. The lithium-sulfur battery has extremely high theoretical specific capacity (1675mAh/g) and theoretical energy density (2600Wh/kg), and is nontoxic in sulfur, rich in raw materials and low in cost, so that the lithium-sulfur battery becomes one of the most promising next-generation energy storage systems.

However, problems still face to realize commercialization of lithium-sulfur batteries, among which lithium polysulfides (Li)₂S_xAnd x is more than or equal to 4 and less than or equal to 8) is a main reason for reducing the coulombic efficiency of the battery and the cycle life of the lithium-sulfur battery. In recent years, researchers have made many studies on how to eliminate the shuttling effect of lithium sulfur batteries to improve the cycle performance of the batteries. One of the most effective methods for preventing the diffusion of polysulfide lithium in organic electrolytes is to confine sulfur in a porous framework, i.e., carbon materials such as carbon nanotubes, mesoporous carbon, carbon spheres, etc. are compounded or coated with sulfur, but the shuttle effect has not been completely solved yet. In the research of the positive electrode material, most methods limit polysulfide by physical or chemical methods, the reuse of polysulfide cannot be well realized, and the electrochemical performance of the battery cannot be effectively improved, so a more effective method for inhibiting the shuttle effect is also required.

Disclosure of Invention

In order to overcome the above-mentioned deficiencies of the prior art, the present invention provides a method for effectively suppressing the shuttling effect of a lithium sulfur battery. The lithium-sulfur battery is arranged at the edge of the disc, the anode of the battery is far away from the circle center, the cathode of the battery is near to the circle center, and the disc is rotated at a constant speed to generate centrifugal force to prevent polysulfide lithium at the anode from diffusing to the cathode in the working process of the lithium-sulfur battery, so that the aim of inhibiting the shuttle effect is fulfilled, and the problems of low coulomb efficiency and poor stability of the battery caused by the shuttle effect in the using process of the lithium-sulfur battery are solved.

In order to solve the problems in the prior art, the invention provides a method for effectively inhibiting the shuttling effect of a lithium-sulfur battery, which comprises the following steps:

step S1, fixing the lithium-sulfur battery at the circumferential edge of the disk capable of rotating at a constant speed;

step S2, making the anode of the lithium sulfur battery far from the circle center and the corresponding cathode of the battery near to the circle center;

and step S3, enabling the disc to rotate at a constant speed, enabling the lithium sulfur battery fixed on the disc to be subjected to centrifugal force generated by the rotation of the disc, and enabling the lithium sulfur battery subjected to the centrifugal force to effectively inhibit the shuttling effect.

In a preferable technical scheme, in the step S1, the radius of the disc is 20-50 cm.

Preferably, in step S3, the rotation speed of the disc is 300-1000 r/min.

Preferably, in step S1, the radius of the disc is 30 cm.

Preferably, in step S3, the rotation speed of the disc is 600 r/min.

Compared with the prior art, the invention creatively provides the method for effectively inhibiting the shuttle effect of the lithium-sulfur battery by adopting the centrifugal force effect, solves the problems of low coulombic efficiency and poor battery stability of the lithium-sulfur battery caused by the shuttle effect in the using process of the lithium-sulfur battery, improves the coulombic efficiency of the lithium-sulfur battery and enhances the cycling stability of the battery; meanwhile, the method provided by the invention is simple in process and easy to realize.

Drawings

FIG. 1 is a schematic diagram of a method of inhibiting shuttling effects in a lithium sulfur battery according to the present invention;

FIG. 2 is a graph of the cycling capacity at 0.2C charge-discharge current for a lithium sulfur battery without the shuttle effect suppression of a lithium sulfur battery according to the present invention;

fig. 3 is a cycle capacity curve of the lithium sulfur battery of example 1 of the present invention 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.

Referring to fig. 1, the present invention provides a method for effectively inhibiting the shuttling effect of a lithium sulfur battery, comprising the following steps:

step S1, fixing the lithium-sulfur battery on the edge of a disk which can rotate at a constant speed and has a radius of 20-50 cm;

step S2, making the anode of the lithium sulfur battery far from the circle center and the corresponding cathode of the battery near to the circle center;

and step S3, rotating the disc at a constant speed of 300-1000 r/min to enable the lithium polysulfide to be subjected to centrifugal force generated by the rotation of the disc.

According to the technical scheme, the lithium-sulfur battery is fixed on the edge of a disc which rotates at a constant speed, wherein the negative electrode of the lithium-sulfur battery is deviated to the side of the circle center, the positive electrode of the battery is far away from the circle center, the disc rotates at a constant speed at a certain speed to generate centrifugal force, so that polysulfide lithium generated by the positive electrode of the lithium-sulfur battery fixed on the edge of the disc cannot diffuse to the negative electrode in the charging and discharging process, and the shuttle effect of the battery is inhibited.

EXAMPLE 1

A button lithium sulfur battery is taken and fixed on the edge of a disk which has the radius of 30cm and can rotate at a constant speed, the anode and the cathode are parallel to the tangential direction of the edge of the disk, wherein the cathode of the lithium sulfur battery is close to the center of the circle of the disk, and the corresponding anode is far away from the center of the circle. The disc is rotated at a constant speed of 600r/min, so that the lithium polysulfide is subjected to the centrifugal force generated by the rotation of the disc.

Instantiation 2

A button-type lithium-sulfur battery is taken and fixed on the edge of a disk which has the radius of 20cm and can rotate at a constant speed, the anode and the cathode are parallel to the tangential direction of the edge of the disk, wherein the cathode of the lithium-sulfur battery is close to the center of the circle of the disk, and the corresponding anode is far away from the center of the circle. And rotating the disc at a constant speed of 300r/min to enable the lithium polysulfide to be subjected to centrifugal force generated by the rotation of the disc.

Instantiation 3

A button-type lithium-sulfur battery is taken and fixed on the edge of a disk which has the radius of 30cm and can rotate at a constant speed, the anode and the cathode are parallel to the tangential direction of the edge of the disk, wherein the cathode of the lithium-sulfur battery is close to the center of the circle of the disk, and the corresponding anode is far away from the center of the circle. Rotating the disc at a constant speed of 1000r/min to make the lithium polysulfide be subjected to the centrifugal force generated by the rotation of the disc.

Instantiation 4

A button-type lithium-sulfur battery is taken and fixed on the edge of a disc which has the radius of 50cm and can rotate at a constant speed, the anode and the cathode are parallel to the tangential direction of the edge of the disc, wherein the cathode of the lithium-sulfur battery is close to the circle center of the disc, and the corresponding anode is far away from the circle center. Rotating the disc at a constant speed of 1000r/min to make the lithium polysulfide be subjected to the centrifugal force generated by the rotation of the disc.

Fig. 2 is a cycle capacity curve of a lithium-sulfur battery without the shuttle effect of the lithium-sulfur battery under the charge and discharge current of 0.2C, and fig. 3 is a cycle capacity curve of the lithium-sulfur battery instantiated 1 according to the present invention under the charge and discharge current of 0.2C, as compared with the above, according to the technical scheme of the present invention, the specific capacity of the lithium-sulfur battery can reach 659mAh/g, and the attenuation rate of 500 cycles is only 0.024%. Examples 2-4 also achieved comparable technical results.

Further, the performance test is carried out on the method. The specific test process is as follows: the negative electrode of the selected lithium-sulfur battery is a lithium sheet, Celgard2325 is used as a diaphragm, 1mLiTFSI is dissolved in 1, 3-Dioxolane (DOL) and ethylene glycol dimethyl ether (DME) (volume ratio is 1:1) to be used as electrolyte, 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.

From the analysis, the method prevents the polysulfide lithium generated by the positive electrode from diffusing to the negative electrode in the charging and discharging process through the centrifugal force generated by the rotation of the disc, so that the shuttle effect of the lithium-sulfur battery is inhibited, the attenuation rate of the assembled battery is only 0.024% each time when the assembled battery is cycled for 500 times at the charging and discharging rate of 0.2C, and the coulombic efficiency is about 99.372%, which shows that the method effectively improves the cycling stability of the battery.

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.