A Carbon Cotton Cathode with Ultrahigh Loading Capability for Statically and Dynamically Stable Lithium Sulfur Batteries.
Sulfur exhibits a high theoretical capacity of 1675 mA h g 1 via a distinct conversion reaction, which is different from the insertion reactions in commercial lithium ion batteries. In consideration of its conversion reaction battery chemistry, a custom design for electrode materials could establish the way for attaining high loading capability while simultaneously maintaining high electrochemical utilization and stability. In this study, this process is undertaken by introducing carbon cotton as an attractive electrode containment material for enhancing the dynamic and static stabilities of lithium sulfur (Li S) batteries. The carbon cotton possessing a hierarchical macro /microporous architecture exhibits a high surface area of 805 m2 g 1 and high microporosity with a micropore area of 557 m2 g 1. The macroporous channels allow the carbon cotton to load and stabilize a high amount of active material. The abundant microporous reaction sites spread throughout the carbon cotton facilitate the redox chemistry of the high loading/content Li S system. As a result, the high loading carbon cotton cathode exhibits (i) enhanced cycle stability with a good dynamic capacity retention of 70% after 100 cycles and (ii) improved cell storage stability with a high static capacity retention of above 93% and a low time dependent self discharge rate of 0.12% per day after storing for a long period of 60 days. These carbon cotton cathodes with the remarkably highest values reported so far of both sulfur loading (61.4 mg cm 2) and sulfur content (80 wt demonstrate enhanced electrochemical utilization with the highest areal, volumetric, and gravimetric capacities simultaneously.
ACS nano