Entropy Engineering-Modulated D-Band Center of Transition Metal Nitrides for Catalyzing Polysulfide Conversion in Lithium-Sulfur Batteries

The sluggish sulfur redox kinetics and severe polysulfide shuttle effect seriously restrict the cycling stability and lower the sulfur utilization of lithium-sulfur (Li-S) batteries. Efficient catalytic conversion of polysulfides is deemed a crucial strategy to address these issues, but still suffers from an unclear electronic structure-activity relationship and a limited catalysis performance. Herein, entropy engineering-induced electronic state modulation of metal nitride nanoparticles embedded within hollow N-doped carbon (HNC) polyhedra are theoretically and experimentally constructed as a catalyst to accelerate the redox process of sulfur and suppress polysulfide migration in Li-S batteries. By introducing V, Cr, and Nb elements to engineer the entropy of TiN, the metal d-band center is optimized to approach the Fermi level, significantly facilitating the conversion of sulfur species. Accordingly, the TiVCrNbN@HNC catalyst enables Li-S batteries to achieve a high initial capacity (1299 mAh g-1 at 0.1 C) and excellent cycling stability with a low capacity decay rate of 0.086% per cycle after 500 cycles. This work may provide a new insight into entropy engineering in catalyst design for high-performance Li-S batteries.