Modification of lithium sulfur batteries by sieving effect: Long term investigation of carbon molecular sieve

Lithium‑sulfur batteries have attracted widespread attention due to their high energy density and low cost. However, commercial application is impeded by the severe “shuttle effect” caused by the dissolution of lithium polysulfides. In this study, commercial carbon molecular sieve (CMS) has been added to investigate its possibility of preventing shuttling due to the sieving effect. The results show that CMS has excellent adsorbing and blocking co-effect that mitigates polysulfides shuttling. In the initial cycle of CMS4.6 at 0.2C, specific capacity reaches to 1191 mAh g−1. With CMS, superior C-rate capacity and cyclic stability are obtained. In addition, the CMS/PP separator improves the compatibility with electrolyte, and reduces charge resistance, thus promoting the transfer rate of lithium ions. Furthermore, in order to prove the practical application of CMS, 1000-cycles long life test at 5C with CR2032 cells and high load with pouch cells are measured. It can be concluded that CMS is a promising material to inhibit the “shuttle effect” and facilitates the commercialization of lithium sulfur batteries due to its commercial availability.