Nanoporous Cobalt–Nitrogen–Carbon Catalyst-Based Multifunctional Interlayer for Enhanced Li–S Battery Performance

The lithium–sulfur battery is considered to be a prospective candidate for the next-generation energy storage system. The practical application of the lithium–sulfur battery is impeded by several existing challenges, especially the lithium polysulfide (LiPS) "shuttle effect," which leads to low utilization of sulfur and poor cycle life. To alleviate the "shuttle effect", herein, we fabricate a nanoporous metal–nitrogen–carbon catalyst, that is, Co–N–C, combined with graphene (G) as a multifunctional separator coating layer. The Co–N–C/G interlayer exhibits several merits to improve the battery performance, including (1) nanoporous structure that facilitates ionic transport, (2) abundant Co active sites and polar nitrogen-rich carbon surface that can adsorb and immobilize LiPSs, (3) highly dispersed Co sites that are able to accelerate the sulfur redox reaction kinetics, and (4) excellent electrical conductivity for further sulphur utilization. The Co–N–C/G-coated separator endows the Li–S battery with excellent cyclic performance and rate capability. This study proposes a guidance to construct functional separators for enhanced lithium–sulfur battery performance.