Built-In Catalysis in Confined Nanoreactors for High-Loading Li-S Batteries.

Cathode host with strong sulfur/polysulfides confinement and fast redox kinetics is an imperious demand for high-loading lithium-sulfur batteries. Recently, porous carbon hosts derived from metal-organic frameworks (MOFs) have attracted wide attention due to their unique spatial structure and customizable reaction sites. However, the loading and rate performance of Li-S cells are still restricted by the disordered pore distribution and surface catalysis in these hosts. Here, we propose a concept of built-in catalysis to accelerate lithium polysulfide (LiPSs) conversion in confined nanoreactors, i.e. laterally stacked ordered crevice-pores encompassed by MoS2 decorated carbon thin-layers. The functions of S-fixability and LiPS-catalysis in these mesoporous cavity reactors benefit from the 2D interface contact between ultrathin catalytic MoS2 and conductive C pyrolyzed from Al-MOF. The integrated function of adsorption-catalysis-conversion endows sulfur infused C@MoS2 electrode with a high initial capacity of 1240 mAh g-1 at 0.2 C, long-life cycle stability of at least 1000 cycles at 2 C and high-rate endurance up to 20 C. This electrode also exhibits commercial potential in view of considerable capacity release and reversibility under high sulfur loading (6 mg cm-2 and ~80 wt%) and lean electrolyte (E/S ratio of 5 μl mg-1). This study provides a promising design solution of catalysis-conduction 2D interface in 3D skeleton to high-loading Li-S batteries.