Borophene-like boron subunits-inserted molybdenum framework of MoB₂ enables stable and quick-acting Li₂S₆-based lithium-sulfur batteries

High-performance lithium-sulfur batteries are limited by the severe “shuttle effect” of polysulfide migration. To entrap and immobilize polysulfides, the development of catalytic material is an effective strategy for improving the lithium-sulfur batteries. Herein, we demonstrate that borophene-like boron subunits-inserted molybdenum frameworks of molybdenum diboride (MoB₂) serves as a polysulfide-anchoring center to power redox reaction processing under the high-efficient electron transfer conditions. Specifically, MoB₂ not only offers active sites to anchor polysulfide via covalent B-B and metallic Mo-Mo bonds-based low lithiation structure, but also provides a high conductivity to accelerate polysulfide conversion kinetics. With these advances, the liquid Li₂S₆-based MoB₂ electrode (area: 2 cm²) offers a high initial capacity of 1116 mAh/g, and holds 558 mAh/g at 2 C after 500 cycles. Furthermore, the currently proposed MoB₂ catalyst may significantly propel the advancement of electrocatalysis technology from lithium-sulfur batteries to metal-air batteries and carbon dioxide/nitrogen electrochemical reduction.