Constructing a LiPAA interface layer: a new strategy to suppress polysulfide migration and facilitate Li+ transport for high-performance flexible Li-S batteries

摘要

Despite many recent attempts to restrict it, the dissolution and diffusion of polysulfides, leading to inferior cycling performance, is still the main bottleneck hindering commercialization of the Li -S battery. Herein, a new strategy of using lithium polyacrylate (LiPAA) to clad multiwalled carbon nanotube/sulfur (MWNT/S) composites as the interface layer for an MWNT/S/LiPAA cathode was proposed, not only to suppress polysulfide migration through physical encapsulation and chemical adsorption, but also to facilitate Li+ diffusion during the charge/ discharge process. Attributed to these functions of LiPAA, MWNT/S/LiPAA exhibited a rate capability and cycling performance superior to those of MWNT/S and MWNT/S/PAA. Moreover, thanks to the introduction of LiPAA, the MWNT/S/LiPAA was endowed with robust mechanical properties, making it suitable for a flexible cathode in a flexible Li-S battery with stable output under deformation. This work could open up a promising way to suppress polysulfide migration for high-performance flexible Li-S batteries.