With the increasing depletion of fossil energy and the increasingly serious problem of environmental degradation, the search for clean, efficient and safe new energy has become a major problem that needs to be solved urgently.

　　With the increasing depletion of fossil energy and the increasingly serious problem of environmental degradation, the search for clean, efficient and safe new energy has become a major problem that needs to be solved urgently. Lithium-sulfur secondary batteries have the advantages of low price, environmental friendliness, and high theoretical specific energy. In particular, sulfur is not only abundant in the earth, but the theoretical capacity and specific energy of sulfur cathode materials are more than 10 times that of traditional lithium battery cathode materials.

　　Lithium-sulfur batteries are recognized as the most ideal alternative to lithium-ion batteries in the future. Once the lithium-sulfur battery is successfully commercialized, it will surely bring a qualitative leap to the electronics, electric vehicle and other industries.

　　However, the most critical problem in the current war is polysulfide, which is an intermediate product that is easily soluble in the electrolyte produced during the charging and discharging of the battery. On the one hand, the dissolution of polysulfides increases the viscosity of the electrolyte and reduces the ionic conductivity; on the other hand, the dissolution of polysulfides causes a rapid loss of active materials, and the performance of the battery is greatly reduced.

　　Therefore, how to reduce the loss of sulfur in the electrolyte and achieve effective "sulfur fixation"? How to design a high-load sulfur cathode to increase the specific energy? These are the key problems that need to be resolved in the current practical application process.

　　Recently, the team of Professor Shun Wang of Wenzhou University, the academician of the Canadian Academy of Engineering, the research group of Professor Zhongwei Chen of the University of Waterloo and the research group of Dr. Jun Lu of the Argonne National Laboratory in the United States published a question on Nat.Commun.2018(9)705 (Nature·Communication) For the academic paper of "Chemisorption of polysulfides through red ox reactions with organic molecules for lithium-sulfurbatteries", the innovative idea of using small organic molecules of anthraquinone to "sulphur fixation" was proposed for the first time, and the long-term cycle stability of high-load sulfur cathodes was realized.

　　Based on this, the researchers proposed a new mechanism of "sulfur fixation" that is different from traditional organic small molecules, that is, through the "chemical adsorption" of small molecules of anthraquinone and soluble lithium polysulfide during charge and discharge, the formation of insoluble in electrolysis The insoluble product of the liquid, thus realizing the effective inhibition of the loss of active material, and significantly increasing the life of the battery.

　　Furthermore, the cost of organic small molecules is low (for example, anthraquinone is less than 50 yuan per kilogram), and the electrode preparation is simple and convenient, and it is easy to synthesize on a large scale. At the same time, it can also easily construct a high-load sulfur electrode to further increase the unit area of the electrode. The mass and specific energy of the battery. In the future, the new technology of small molecule "sulfur fixation" is expected to greatly shorten the process of commercialization of high-performance lithium-sulfur batteries.

　　In short, this research result reveals the important role of organic small molecules on the cycle performance of lithium-sulfur batteries. Based on the traditional research of lithium-sulfur batteries, a new research direction is proposed-small molecules help build high-performance lithium-sulfur batteries. This research will enable the development of lithium-sulfur batteries to a new level.