Cable-Shaped Lithium-Sulfur Batteries Based on Nitrogen-Doped Carbon/Carbon Nanotube Composite Yarns

The research on flexible and wearable devices has attracted extensive attention in the last few years. Lithium-sulfur (Li-S) batteries are regarded as a promising option because of their high theoretical capacity and energy density. Here, cable-shaped Li-S batteries are developed based on a nitrogen-doped carbon/carbon nanotube/sulfur (NCNT/S) composite cathode and lithium metal anode. The carbon nanotube (CNT) yarns with high conductivity and an appropriate amount of doped nitrogen are synthesized by wet-spinning followed by a carbonization process, and further act as a self-supported conductive backbone for the active material. The NCNT/S yarns exhibit a high initial capacitance of 1001 mAh g(-1) and excellent cyclic stability with 87% capacity retention after 200 cycles at 0.5 C. Furthermore, the assembled cable-shaped Li-S batteries by NCNT/S yarns present good ability to light up the LEDs for more than 8 h under normal and bending states at various angles, indicating that the cable-shaped Li-S batteries could be a prospective candidate for application in wearable electronics.