Molecular engineering of N-rich ZIF-integrated graphene composite interface for efficient physiochemical confinement and catalytic conversion of polysulfides in lithium-sulfur batteries

Abstract

Lithium-sulfur (Li-S) batteries are regarded as one of the most promising energy storage systems because of their high theoretical specific capacity, energy density, low cost, and environmental benignancy. However, the practical application of Li-S batteries has been hindered by inevitable polysulfides shuttling behavior, the sluggish redox kinetics, and poor electrical conductivity of sulfur, which lead to rapid capacity decay and low active material utilization. In this study, we report a multifunctional layer consisting of N-rich zeolitic imidazolate frameworks (ZIF)/reduced graphene oxide (rGO) composite (NZG) as an electrocatalyst to overcome the drawbacks of Li-S batteries. During the preparation of NZG, deamination of the ZIF8A induces the incorporation of abundant N-containing moieties into rGO (pyridinic and pyrrolic N), which results in providing favorable active sites for polysulfides confinement and their rapid conversion via physiochemical interactions. Additionally, hierarchical pores with large surface area and interconnected conductive pathways in the as-prepared multifunctional layer accelerate the catalytic conversion kinetics of polysulfide species, leading to high sulfur utilization and enhanced Li-S battery electrochemical performance. This work suggests an efficient approach for designing multifunctional layers to achieve high-performance Li-S batteries.