Promoting Electrocatalytic Conversion of Polysulfide using Cobalt Disulfide Nanocrystals for Lithium Sulfur Batteries

Lithium sulfur batteries provide one of the most attractive opportunities for next generation energy storage devices benefiting from their particularly high energy density. However, the obstacle mainly originating from the sluggish conversion kinetics between the soluble lithium polysulfide immediate and S/Li2S/Li2S2 results in lithium sulfur batteries with low sulfur usage and coulombic efficiency, poor cycling, and rate performance. In this work, a new cathode host material with cobalt disulfide nanoparticles supported on reduced graphene oxides (GOs) has been designed to enhance the interactive affinity to lithium polysulfide and accelerate polysulfide conversion more effectively. With the implementation of these metal chalcogenides, a sulfur cathode with low polarization, stable cycling performance, and high rate capability is obtained. Moreover, this work offers solid evidence from the post mortem analysis of symmetric cells such as SEM and XPS, confirming the origin of the catalytic effects from cobalt disulfide nanocrystals wrapped with reduced GOs in a sulfur battery.