With the eager demand for high-capacity energy storage devices for emerging electronic products such as portable electronic devices and electric vehicles, lithium-sulfur batteries (Li-S) have advantages such as high theoretical specific capacity and energy density, and low cost and environmental friendliness of sulfur. It is considered one of the most promising high-capacity storage systems. However, commercial applications of Li-S batteries still have some technical challenges, such as the insulation of solid sulfides, the shuttle effect of soluble long-chain polysulfides, and the large variation in the volume of sulfur during charge and discharge. These problems often result in low sulfur utilization, poor cycle life, and even a series of safety issues. How to significantly improve the stability of Li-S batteries while increasing their high-power discharge performance has become one of the hot spots in current research.
Researcher Wang Ruihu of the State Key Laboratory of Structural Chemistry of the Fujian Institute for the Study of Structure of the Chinese Academy of Sciences collaborated with Professor Yang Zhi of Wenzhou University to compound water vapor-etched porous NbS2 and highly conductive iodine-doped graphene (IG) into a ternary mixture. In the sulfur cathode system, sandwich-type NbS2@S@IG cathode materials coated with IG were synthesized. In this special sandwich structure, the highly polar and strong affinity of layered NbS2 promotes the physical interception and chemisorption of polysulfides, and solves the problem of polysulfide dissolution and shuttle effects synergistically; the high conductivity and porosity of NbS2 The rate increases the interfacial charge transfer and ion migration, thereby improving the electrochemical kinetics of the redox reactions of Li-S cells; the sandwich structure surrounded by IG can not only make close contact between sulfur species and layered NbS2 (or IG). In addition, it can withstand large volume fluctuations of sulfur cathode during charge and discharge. The Li-S battery assembled by NbS2@S@IG exhibits excellent cycle stability at a high rate of 20-40C.
The research results were published on the ACS Nano. The research work was funded by the National Natural Science Foundation of China and the Chinese Academy of Sciences' strategic pilot technology project.
Spring Pull-Out Sink Faucet,Pull Out Spring Kitchen Tap,Pull Out Spring Neck Taps,Spring Pull Out Sink Faucet
Heshan Janno Kitchen and Bath Technology Co.,Ltd , https://www.janno-ks.com