Cobalt hydroxide decorating N-doped hollow carbon sphere as a new sulfur host to improve long cycle stability in lithium–sulfur batteries

Abstract

Lithium–sulfur batteries possess high specific capacity and low raw material costs, are considered to be a candidate for replacing traditional lithium-ion batteries. However, the shuttle effect of polysulfide and the low conductivity of sulfur seriously hinder the practical application of lithium–sulfur batteries. Herein, we proposed a hollow porous carbon sphere (HCS) doped with Co(OH)2 as the cathode of lithium–sulfur battery to suppress the shuttle effect. The hollow carbon sphere structure not only restricts the migration of polysulfide, but also improves the overall conductivity of the material, and provides a larger cavity to buffer the expansion of battery during the charging and discharging process. The lithium–sulfur battery using Co(OH)2/HCS composite electrode as cathode delivers initial specific capacity of 865 mAh g⁻¹ at 0.2 C and retains high capacity of 641 mAh g⁻¹ after 400 cycles at 0.2 C with low fading rate(FR) of 0.134% per cycle.