All-in-One Sulfur Host: Smart Controls of Architecture and Composition for Accelerated Liquid–Solid Redox Conversion in Lithium–Sulfur Batteries

The development of Li–S batteries (LSBs) is largely impeded by sluggish redox kinetics and notorious polysulfide shuttling. Herein, hierarchical MoC@Ni–NCNT arrays are reported as a multifunctional sulfur host in Li–S batteries, which comprised a flexible carbon fiber cloth substrate decorated with vertical MoC porous nanorods rooted by interconnected nitrogen-doped carbon nanotubes (NCNTs). In the designed host, the inner MoC porous backbone (composed of nanoparticles) along with the in situ-grafted interwoven NCNT shell can greatly maximize the host–guest interactive surface for homogeneous sulfur dispersion, thus realizing decent high-sulfur-loading performance. Ni nanoparticles, encapsulated within NCNTs in the outer shell, act as strong chemical-anchoring centers effectively trap-escaped polysulfides and propel the bidirectional sulfur transformation kinetics. In merit of sufficient adsorption and catalytic sites, the cell configured with the MoC@Ni–NCNT cathode delivers not only high capacity (1421 mA h g–1 at 0.1 C) but also superior rate performance and ultralong lifespan. The cell can still achieve a superb areal capacity of 6.1 mA h cm2 under an increased sulfur loading up to 6 mg cm–2. This work could open a new avenue for the construction of a multifunctional cathode for high-performance LSBs.