Preparation method of gel electrolyte for lithium-sulfur battery

Abstract

The invention relates to a preparation method of a gel electrolyte for a lithium-sulfur battery. The method comprises the following steps: 1, preparing an electrolyte lithium salt and an organic solvent into a basic electrolyte; 2, adding a mixed liquid of a polymeric monomer, a cross-linking agent and a solvent into the basic electrolyte to prepare a cross-linking polymeric liquid; 3, adding an initiator into the cross-linking polymeric liquid, performing initiated polymerization at a temperature of 15-45 DEG C for 2-6 hours to finish a preparation process of the gel electrolyte for the lithium-sulfur battery, and injecting the gel electrolyte into the lithium-sulfur battery which is being assembled. According to the preparation method, the gel electrolyte formed after initiated polymerization is put into the lithium-sulfur battery in an assembling process, and the battery has a relatively high capacity retention ratio no matter the battery is under a high temperature condition or a low temperature condition, so that high and low temperature adaptability of the lithium-sulfur battery is improved effectively; a manufacturing process of the battery is improved; and the manufacturing cost of the battery is lowered. The preparation method is suitable for large-scale commercial production of the lithium-sulfur battery.

Description

technical field [0001] The invention belongs to the technical field of lithium-sulfur batteries, in particular to a method for preparing a gel electrolyte for lithium-sulfur batteries. Background technique [0002] Lithium-sulfur battery is a kind of lithium battery. It uses sulfur as the positive electrode and lithium metal as the negative electrode. The specific capacity is as high as 1675mAh / g, which is much higher than other commercial lithium-ion battery positive materials, and sulfur is An environmentally friendly element, basically no pollution to the environment, is a very promising lithium battery. However, the shortcomings of the currently known lithium-sulfur batteries are: (1) lithium polysulfide compounds are dissolved in the electrolyte; (2) sulfur, as a non-conductive substance, has very poor conductivity, which is not conducive to the high rate performance of the battery; In the process, the expansion and contraction of the volume are very large, which may c...

AI Technical Summary

Problems solved by technology

However, the shortcomings of the currently known lithium-sulfur batteries are: (1) lithium polysulfide compounds are dissolved in the electrolyte; (2) sulfur, as a non-conductive substance, has very poor conductivity, which is not conducive to the high rate performance of the battery; In the process, the expansion and contraction of the volume are very large, which may cause the battery to be damaged; in order to inhibit the dissolution of sulfur and improve the cycle performance of the battery, ether organic solvents are usually used as the electrolyte and some additives are added at the same time. This method works well at room temperature , but the effect is not ideal at higher temperatures (above 45 degrees)

The method is to prepare a gel film and coat it on the surface of the sulfur compound, which improves the cycle performance of the battery at room temperature and simplifies the process on the basis of the existing technology, but it is still difficult to improve the cycle performance of the battery at high temperature (45 degrees)