High-dimensional strain unlocks fast polysulfide redox kinetics for lithium-sulfur batteries
Jin‐Lin Yang, Hengyue Xu, Tao Xiao, Jia Li, Wenqi Yan, Tao Zhang, Hong Jin Fan
Abstract
Strain engineering is an effective approach to enhancing the activity of catalysts by tuning the electrical and geometric configurations. However, the impact of strain dimension on the sulfur redox kinetics and polysulfide adsorption configuration has yet been deciphered. Herein, we employ a biaxial-strained dichalcogenide catalyst with highly curved basal planes to activate the reserve metal atoms and realize efficient lithium-sulfur batteries. The high-dimensional strain enhances the exposure of Mo sites, thereby shifting the polysulfide adsorption mechanism from weak Li-S/Se bonding to strong S*-Mo bonding. Moreover, biaxial strain upshifts both d and p band centers, fostering the interfacial charge transfer and catalytic activity. Based on this mechanism, we obtain apparent correlations between biaxial strain and apparent activation energy for sulfur species conversion. This d-p hybridization dominated catalytic mechanism leads to obvious enhancement in capacity retention and rate performance. We showcase a 6 Ah-level multilayer pouch cell with a specific energy of 396 Wh kg–1 (based on masses of all components). Strain engineering is effective in modulating catalyst activity. Here, authors report a high-dimensional biaxial strained dichalcogenide catalyst to unlock inner metal sites, which accelerates sulfur redox kinetics and enables lithium–sulfur pouch cells with increased capacity and cycling stability.