Nanoheterocrystal Catalysts Designed by Multiple Reactivity Descriptors for Accelerated Redox Kinetics in Li-S...

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, d-band center, and structural factors as multiple reactivity descriptors to manipulate the d-orbital of the nanoheterocrystal catalyst. Among these metal/NbC model catalysts, Co/NbC exhibits an elevated Nb d-band center and extra Co d-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.