Lai Yuchong, Nie Huagui, Xu Xiangju, Fang Guoyong, Ding Xinwei, Chan Dan, Zhou Suya, Zhang Yonggui, Chen Xi'an, Yang Zhi
Key Laboratory of Carbon Materials of Zhejiang Province, College of Chemistry and Materials Engineering , Wenzhou University , Wenzhou 325035 , PR China.
ACS Appl Mater Interfaces. 2019 Aug 21;11(33):29978-29984. doi: 10.1021/acsami.9b10049. Epub 2019 Aug 8.
The complicated reactions at the cathode-electrolyte interface in Li-S batteries are a large barrier for their successful commercialization. Herein, we developed a molecular design strategy and employed three small molecules acting as interfacial mediators to the cathodes of Li-S batteries. The theoretical calculation results show that the incorporation of tris(4-fluorophenyl)phosphine (TFPP) has a strong binding performance. The experimental results demonstrate that the strong chemical interactions between polysulfides and the F, P atoms in TFPP not only modify the kinetics of the electrochemical processes in the electrolyte but also promote the formation of short-chain clusters (LiS, = 1, 2, 3, and 4) at the interface during the charge-discharge process. As a result, an optimized electrode exhibits a low capacity decay rate of 0.042% per cycle when the current rate is increased to 5 C over 1000 cycles.
锂硫电池中阴极-电解质界面处的复杂反应是其成功商业化的一大障碍。在此，我们开发了一种分子设计策略，并采用了三种小分子作为锂硫电池阴极的界面介质。理论计算结果表明，三（4-氟苯基）膦（TFPP）的引入具有很强的结合性能。实验结果表明，多硫化物与TFPP中的F、P原子之间的强化学相互作用不仅改变了电解质中电化学过程的动力学，而且在充放电过程中促进了界面处短链簇（LiS，n = 1、2、3和4）的形成。结果，当电流速率在1000次循环中增加到5 C时，优化后的电极表现出每循环0.042%的低容量衰减率。
