A triple-functional carbon molecular sieve (CMS) that addresses the performance trilemma in practical lithium sulfur batteries. (25th January 2023) - Ghasemiestahbanati, Ehsan
Abstract: Lithium-sulfur batteries offer an attractive energy storage alternative independent of critical minerals such as cobalt or nickel. However, their inadequate stability under long term cycling, and storage capacity on a volumetric basis hampers their uptake. These limitations can be addressed by seeking to control the formation and crossover of polysulfides, oligomers generated through reaction of solvated sulfur moieties with the lithium anode, and by seeking to restrict the consumption of active materials. Here, we report the development of a triple-functional carbon molecular sieve (CMS) interlayer. The microporous, polar, and conductive structure of the CMS provides physisorption, chemisorption, and reactivation capabilities concurrently. Therefore, the soluble polysulfides can be trapped, suppressed from shuttling, and reutilized to not only improve the kinetics of the redox reaction but also hinder the loss of active materials. As a result, our CMS-based Li–S batteries deliver combined exceptional gravimetric (1282 mAh g −1 ) and areal (7.05 mAh cm −2 ) capacities at 0.1 C rate as well as cycling stability up to 1000 cycles at 0.2 C rate over 9 months. Graphical abstract: A triple-functional PIM-1 derived carbon molecular sieve (CMS) interlayer provides polysulfide physisorption, chemisorption, and reactivation capabilities to address a "performance trilemma" facing the development of practical Li–S batteries. At current rate of 0.2 C, our CMS-based Li–S batteries deliver combined high gravimetric capacity (1028 mAh g −1 ), areal capacity (5.65 mAh cm −2 ), and capacity retention (75% after 500 cycles). Image 1