Bimetallic selenides heterostructure embedded in urchin-like core/shell conductive rhombic dodecahedron as sulfur host for high-energy-density lithium-sulfur battery.

Lithium-sulfur (Li-S) batteries, characterized by the exceptional theoretical energy density, have emerged as a highly up-and-coming competitor for next-generation power batteries. However, the notorious shuttle effect of lithium polysulfides (LiPSs) and sluggish redox reaction kinetics, particularly under high S loading and lean electrolyte, significantly impeded the commercialized progress of Li-S batteries. Herein, we rationally designed and synthesized a novel urchin-like core/shell rhombic dodecahedron as a S host for the first time, wherein the nanoparticles of bimetallic selenides (CoSe/SbSe) heterojunction are uniformly encapsulated within nitrogen-doped carbon layer and spiny-like CNTs (NC-CNTs) (denoted as CoSe/SbSe@NC-CNT). The well-distributed CoSe/SbSe heterostructure endows the carbon frame with excellent adsorptivity, catalyzing and conductivity towards LiPSs, enhancing the redox kinetics. Benefiting from these superior properties, the remarkable electrochemical performances exhibit in Li-S batteries. At a high rate of 2 C, after an ultra-long and stable 1000 cycles, the capacity reaches 818.8 mAh g, accompanied by an ultralow decay of 0.021 % per cycle from coin battery. Notably, even under high S loading (10.2 mg cm) and limited electrolyte (E/S, 3.47 μL mg), it still achieves a high areal capacity of 8.14 mAh cm (specific capacity of 797.8 mAh g) after 100 cycles at 0.5 C. More strikingly, for pouch battery, it obtains a specific capacity 600.5 mAh g (2.76 mAh cm) after 150 cycles at 1 C. Designing and developing a novel heterostructure is a promising strategy, which can enhance high S utilization and extend long-cycle life for the high-energy-density in Li-S battery.