In situ grown α-Cos/Co heterostructures on nitrogen doped carbon polyhedra enabling the trapping and reaction-intensification of polysulfides towards high performance lithium sulfur batteries.

Lithium sulfur (Li-S) batteries are considered as one of the most promising next generation energy storage systems, whereas their intrinsic drawbacks impeded their practical implementation. Herein, a nitrogen doped porous carbon polyhedron coupled with a well distributed α-CoS/Co heterostructure mediator was designed and prepared as the sulfur cathode host for lithium sulfur batteries. The α-CoS/Co heterostructure on a 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 mA h g-1 first discharge capacity and a well satisfactory 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 mA h g-1 specific capacity for a high sulfur loading of 4.8 mg cm-2 with remarkable cycling performance.