Electrocatalytic Polysulfide Traps for Controlling Redox Shuttle Process of Li–S Batteries

Abstract

Stabilizing the polysulfide shuttle while ensuring high sulfur loading holds the key to realizing high theoretical energy of lithium-sulfur (Li-S) batteries. Herein, we present an electrocatalysis approach to demonstrate preferential adsorption of a soluble polysulfide species, formed during discharge process, toward the catalyst anchored sites of graphene and their efficient transformation to long-chain polysulfides in the subsequent redox process. Uniform dispersion of catalyst nanoparticles on graphene layers has shown a 40% enhancement in the specific capacity over pristine graphene and stability over 100 cycles with a Coulombic efficiency of 99.3% at a current rate of 0.2 C. Interaction between electrocatalyst and polysulfides has been evaluated by conducting X-ray photoelectron spectroscopy and electron microscopy studies at various electrochemical conditions.