Defect Strategy‐Regulated MoSe2‐Modified Self‐Supporting Graphene Aerogels Serving as Both Cathode and Interlayer of Lithium‐Sulfur Batteries

Abstract

AbstractThe severe shuttle effect and the sluggish redox reaction kinetics are the two most urgent issues with lithium‐sulfur batteries (LSBs). In this work, Se vacancy‐rich molybdenum selenide‐modified graphene aerogels are designed to serve as both cathode host (MoSe2‐x@GA/S) and freestanding interlayers (MoSe2‐x@GA) for LSBs. The graphene network‐supported binder‐free sulfur host maximizes electron conductivity/Li+ migration rate and alleviates bulk expansion. The defect‐rich MoSe2‐x with sulfiphilic‐lithiophilic properties accelerates the nucleation and dissociation of Li2S, while the insertion of a bifunctional interlayer not only facilitates the adsorption and conversion of polysulfides but also regulates the uniform lithium deposition and inhibit the growth of lithium dendrites. As a result, the assembled MoSe2‐x@GA/S+interlayer electrode obtains good feedback in terms of capacity enhancement and cycling stability, possessing a high initial discharge capacity of 1256.9 mA h g−1 at 0.2 C and a slow decay ratio of 0.024% per cycle at a high current density of 1 C after 1000 long‐term cycling, and achieve high specific capacity (720.6 mA h g−1) at high sulfur loading (4.8 mg cm−2) and lean electrolyte (5.5 µL mg−1) conditions. This insightful work contributes new ideas for the design of binder‐free sulfur host and the application of defective electrocatalytic engineering.