Carbon-dispersed Carbon Nanotube Film Electrode Incorporated with Sulfur for Long-Life Li-S Batteries

摘要

Free-standing carbon nanotube (CNT) frameworks have been found to be highly effective in increasing sulfur loading and energy density of lithium-sulfur (Li-S) batteries. This owes to their ability to accommodate a large amount of sulfur in their interspaces. Also, this solution docs require neither a binder nor a current collector. As a drawback, the application of free-standing CNT frameworks suffers from the abundance of their inherent macroporosities, as these promote the diffusion of polysullides. In this work, we address this issue by incorporating disordered mesoporous carbon (DMC), as a polysulfide reservoir, into a CNT matrix to form CNT-DMC hybrid film. We apply facile hot-pressing lo incorporate sulfur into the composite electrode. Furthermore, we determine the electrochemical performances of CNT-DMC/sulfur (S) cathode by a galvanostatic method. We find that the CNT-DMC/S cathode exhibits a high initial capacity of 1032 mAh/g at 0.25 C and a superior capacity retention of 92% after 100 cycles, compared to sulfur-impregnated CNT cathode. We attribute these enhancements to the efficient polysulfide absorption ability of DMC. This novel approach bears a high potential for the development of high-performance Li-S batteries with flexible sulfur cathodes.