Metal–organic framework derived yolk–shell NiS2/carbon spheres for lithium–sulfur batteries with enhanced polysulfide redox kinetics

Abstract

Yolk–shell NiS₂/carbon spheres (yolk–shell NiS₂/C) have been synthesized by one-step annealing of yolk–shell Ni-metal–organic framework spheres. In particular, both the inner yolk sphere and the outer shell of yolk–shell NiS₂/C can provide catalytically active sites for the redox of polysulfide confined in the yolk–shell structure, providing enhanced redox kinetics. A yolk–shell NiS₂/C–sulfur cathode exhibits a high rate capacity of 569 mA h g⁻¹ at 2C and shows excellent cycling stability, demonstrating the superiority of the yolk–shell structure.