Preparation method of a novel lithium-sulfur battery diaphragm material

Abstract

The invention relates to a preparation method of a novel lithium-sulfur battery diaphragm material, comprising the following steps: step A, preparing polystyrene PS microspheres; step B, preparing 3Dzif8 material; step C, preparing Co-3Dzif8 material; step D, carbonizing Co‑3Dzif8 material. The invention overcomes the defects of obvious polysulfide "shuttle effect" in the lithium-sulfur battery prepared by the prior art, significant volume expansion effect of the lithium-sulfur battery and unstable electrochemical performance of the battery, and simplifies the production process and reduces the production cost. cost.

Description

technical field [0001] The invention relates to the technical field of material chemistry, in particular to a preparation method of a novel lithium-sulfur battery diaphragm material, and more particularly to a preparation method of a metal organic framework material as a diaphragm material. Background technique [0002] With the progress and development of social productivity, the level of human productivity has been greatly improved. At the same time, human demand for energy is also increasing day by day, and energy has an increasing influence on modern society and life. Energy has become one of the key factors affecting social development. Traditional fossil fuels (coal, petroleum) are non-renewable resources. Studies have shown that the current oil reserves on the earth can only be exploited for about 50 years, and coal resources can only last for less than 100 years. Mankind is facing an unprecedented energy crisis. In addition, the use of traditional fossil fuels has ...

AI Technical Summary

Problems solved by technology

The shuttle effect reduces the utilization of sulfur electrode active materials

At the same time due to Li 2 S and Li 2 S 2 It cannot be dissolved in the electrolyte and deposited on the surface of the lithium anode, which further reduces the performance of the lithium-sulfur battery

The conductivity of elemental sulfur is very poor, and the conductivity at room temperature is low (5×10-30S cm -1 ), due to the absence of ionic sulfur, it is difficult to activate sulfur as a cathode material, and the lithium sulfide generated by the battery electrode during the reaction will dissolve in the electrolyte, resulting in a shuttle effect (or shuttle effect), thus causing lithium-sulfur Loss of battery active material and reduced service life

The final product of the electrode reaction is Li 2 The conductivity of S is also poor, and it will be deposited on the sulfur electrode, and the migration speed of lithium ions in solid lithium sulfide is very slow, thus slowing down the electrochemical reaction kinetics of the battery.

Due to sulfur and the final product Li 2 The density of S is different, and the sulfur cathode will undergo a large volume change before and after the electrode reaction, so the electrode is easily pulverized during multiple cycles, resulting in damage to the battery

[0008] In order to solve the above problems, it has been proved that the modification of the diaphragm can significantly inhibit the shuttle effect of polysulfides and play a role in capturing polysulfides. However, although the existing technology has improved the performance of lithium-sulfur batteries to a certain extent, But the common disadvantages are: the electrochemical performance of the battery is unstable, the specific capacity is not high enough, the shuttle effect of polysulfide is still obvious, the volume expansion of lithium-sulfur ion battery is significant, the experiment is more complicated, the operation is difficult, and the production cost is high.

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