Understanding Heterogeneous Electrocatalysis of Lithium Polysulfide Redox on Pt and WS2 Surfaces

An electrocatalytic cathode surface in a Li-sulfur cell can alleviate intrinsic issues such as polysulfide shuttling by improving their adsorption and the reaction kinetics. Herein, we carried out fundamental electrochemical studies on the sulfur-electrocatalyst interface to develop a suitable catalytic cathode. The potentiodynamic and potentiostatic methodologies were used to infer diffusion, adsorption, and kinetic behaviors of polysulfides with respect to catalytic and noncatalytic interfaces. Also, we have demonstrated the influence of catalyst on solid-to-liquid and liquid-to-solid polysulfides reaction kinetics and their effect on Li2S nucleation ending up in gaining high capacity during the discharge process. In addition, we have explained in detail the impact of catalytic interface on cathode surfaces as well as on the reversibility of sulfur redox chemistry.