Flexible sulfur wires (Flex-SWs)—A new versatile platform for lithium-sulfur batteries

In this paper, a simple electrospinning methodology is described for generating novel fiber configurations of sulfur with the potential of yielding high performance sulfur electrodes for use in lithium-sulfur batteries. The unique fiber morphology derived by electrospinning has the capability of generating flexible sulfur yarns for the first time rendering them a highly attractive platform for small-scale mobile device applications such as textile-batteries. The electrospinning methodology reported herein also allows for the formation of a polymer-sulfur interface which acts as a physical barrier to liquid lithium electrolyte facilitating the reduction of polysulfide dissolution, a primary barrier to the progress of Li-S systems. Such flexible sulfur wire materials when converted into pellet sulfur electrodes, exhibit very stable capacities over 135 cycles with high areal capacities (~2.5 mAh cm-2). Finally, coating the electrodes with an inorganic lithium ion conductor coating results in further improvement of cycling behavior with electrodes of ~650 mAh g-1 capacity and an impressive low fade rate of ~0.003% fade cycle-1 demonstrating the promise of this unique platform.