Nanoheterocrystal Catalysts Designed by Multiple Reactivity Descriptors for Accelerated Redox Kinetics in Li–S Batteries

Heterogeneous transition metal nanocrystals with charge redistribution interfaces serve as effective lithium polysulfide (LiPS) absorption and conversion catalysts in lithium-sulfur (Li-S) batteries. However, the rational design principle for the coupling relationship of nanoheterocrystals remains unclear. Here, we employ the binding energy, <i>d</i>-band center, and structural factors as multiple reactivity descriptors to manipulate the <i>d</i>-orbital of the nanoheterocrystal catalyst. Among these metal/NbC model catalysts, Co/NbC exhibits an elevated Nb <i>d</i>-band center and extra Co <i>d</i>-band catalytic center, thereby simultaneously delivering strong LiPS absorption, fast redox kinetics, and dense product deposition. Hence, Li-S batteries using the Co/NbC@NC catalyst demonstrate the rate performance and cycle stability with a low capacity decay rate of 0.059% per cycle over 500 cycles at 3C. High sulfur utilization is also evidenced by 554.2 mAh g^-1 at a low temperature of -30 °C and 4.75 mAh cm^-2 under a high mass loading of 6.5 mg cm^-2. This work presents a rational design paradigm to stimulate the development of high-performance nanoheterocrystal catalysts.