In Situ Grown α-Cos/Co Heterostructure on Nitrogen Doped Carbon Polyhedron Enabling Trapping and Reaction-intensifying of Polysulfides towards High Performance Lithium Sulfur Battery
Lithium sulfur (Li-S) battery is considered as one of the most promising next generation energy storage systems, whereas its intrinsic drawbacks impeded its practical implementation. Herein, a nitrogen doped porous carbon polyhedron coupled with well distributed α-CoS/Co heterostructrue mediator was designed and prepared as the sulfur cathode host for lithium sulfur battery. The α-CoS/Co heterostructrue on nitrogen doped carbon polyhedron (NCP) not only provides a strong adsorption interaction towards soluble polysulfides, but more importantly, also promotes the fast conversion of polysulfides to insoluble products, chemically suppressing the shuttling of polysulfides through the simultaneous advantages of α-CoS and Co. As a result, the α-CoS/Co-NCP-S cathode exhibits high sulfur utilization with a 1611.4 mAh g-1 first discharge capacity and a well satisfied redox cycling stability with a low capacity fade rate of 0.042% per cycle at 0.5 C for over 800 cycles. Moreover, the hybrid cathode delivers 860.2 mAh g-1 specific capacity for high sulfur loading of 4.8 mg cm-2 with remarkable cyclic performance.