Cage-confinement synthesis of MoC nanoclusers as efficient sulfiphilic and lithiophilic regulator for superior Li–S batteries

High-energy-density Li-S batteries are subjected to serious sulfur deactivation and short cycle lifetime caused by undesirable polysulfide shuttle effect and frantic lithium dendrite formation. In this work, a controllable cage-confinement strategy to fabricate molybdenum carbide (MoC) nanoclusters as a high-efficient sulfiphilic and lithiophilic regulator to mitigate the formidable issues of Li-S batteries is demonstrated. The sub-2 nm MoC nanoclusters not only guarantee robust chemisorption and fast electrocatalytic conversion of polysulfides to enhance the sulfur electrochemistry, but also homogenize Li⁺ flux to suppress the lithium dendrite growth. As a consequence, the MoC-modified separator endows the batteries with boosted reaction kinetics, promoted sulfur utilization, and improved cycling stability. A reversible capacity of 701 mAh·g⁻¹ at a high rate of 5.0C and a small decay rate of 0.076% per cycle at 1.0C over 600 cycles are achieved. This study offers a rational route for design and synthesis of bifunctional nanoclusers with both sulfiphilicity and lithiophilicity for high-performance Li-S batteries. Graphical abstract: [Figure not available: see fulltext.]