Enhancing the Catalytic Activity of Layered Double Hydroxide Supported on Graphene for Lithium–Sulfur Redox Reactions

The lithium–sulfur battery is one of the next-generation rechargeable battery candidates due to its high theoretical energy density and low cost. However, the sluggish conversion kinetics of soluble lithium polysulfides into insoluble Li2S2/Li2S leads to low sulfur utilization, retarded rate responses, and rapid capacity decay. Here, we enhance the sulfur reduction kinetics by designing and synthesizing a lamellar-structured NiFeLDH and reduced graphene oxide (rGO) composite. The assembly of a two-dimensional NiFeLDH with rGO, which has high conductivity and electrocatalytic activity, significantly enhances the electrochemical steps of sulfur reduction. The S@NiFeLDH/rGO cathode delivers an initial discharge capacity of 1014 mAh g−1 at 0.2 C and a capacity of 930 mAh g−1 after 100 cycles at 0.2 C. Even at a high current density of 1 C, the S@NiFeLDH/rGO could maintain a high capacity of 554 mAh g−1 after 400 cycles.