Towards flexible lithium-sulfur battery from natural cotton textile

Highlights: •Tubular activated cotton textile (ACT) was derived from natural cotton textile. •ACT was used as sulfur host to prepare ACT/S composite. •Reduced graphene oxide (rGO) nanosheets were coated around ACT. •KOH-activated ACT was used as interlayer between cathode and separator. •The assembled cell exhibited an exceptional capacity and rate performance. -- Abstract: The future wearable/portable electronics need flexible power sources with higher storage capability. Lithium-sulfur (Li-S) battery is very promising for the development of next-generation high-energy battery due to its ultra-high theoretical capacity. However, the development of flexible Li-S battery has been plagued by its fast capacity decay and lack of suitable flexible substrates. Herein, a conductive activated cotton textile (ACT) with porous tubular structure was first derived from natural cotton textile to load sulfur, which was further wrapped with partially reduced graphene oxide (ACT/S-rGO) to immobilize lithium polysulfides. Meanwhile, the partially reduced graphene oxide nanosheets could be served as a conductive coating, which further mitigated the poor conductivity of sulfur and enabled fast electron transportation along ACT fibers. Furthermore, a KOH-activated ACT with micropore size distribution was inserted between cathode and separator to mitigate the "shuttle effect" of polysulfides. Finally, the assembled ACT/S-rGO cathode with porous ACT interlayer exhibited an exceptional rate capability and durable cyclic performance (with a well-retained capacity of ∼1016 mAh g⁻¹ even after 200 cycles). A flexible Li-S cell with ACT/S-rGO as a cathode was also assembled to demonstrate its superior potential as flexible power sources for future wearable electronic devices.