Construction of binary metal sulfide nanoparticles to boost catalytic activity for lithium-sulfur batteries

Lithium-sulfur batteries (LSBs) are considered viable options for the next generation of energy storage devices owing to their remarkable theoretical advantages. However, the further practical implementation the LSBs is hindered by certain challenges, including the shuttle effect and the slow reaction kinetics associated with soluble lithium polysulfides (LiPSs). Herein, Co9S8-MoS2/PC nanoparticles with a polyhedral structure are designed as effective host materials to tackle these challenges. The electrocatalysis activity of Co9S8-MoS2/PC nanoparticles can be maximized via tuning the ratio of metal ions in the precursor. The experimental results reveal that Co9S8-MoS2/PC nanoparticles could enhance the transfer of electrons and ions, reinforce the interaction with LiPSs, and accelerate the redox reaction kinetics of LiPSs. The LSBs with optimal S@Co9S8-MoS2/PC(5:1) cathode achieve an enhanced rate capability, a high specific capacity, and long cycle life with a capacity decay of 0.059 % per cycle over 500 cycles at 0.5C. This work demonstrates the great potential of binary metal sulfide nanoparticles for the effective conversion of LiPSs in LSBs.