Achieving Cycling Durability of Lithium-Sulfur Batteries via Capturing Polysulfides through a Three-Dimensional Interconnected Carbon Network Anchored with Ultrafine FeS Nanoparticles.

Abstract

Shuttle effect has always been a critical obstacle to the application of lithium-sulfur (Li-S) batteries for leading to unstable cycle performance and a short lifespan. To solve this problem, a particular strategy is put up to relieve shuttle effect by capturing soluble polysulfides through a three-dimensional interconnected carbon network. Due to the uniformly anchored ultrafine FeS nanoparticles on a 3D interconnected carbon network, the material could lock soluble polysulfides on the cathode side and promote electrochemical conversion reactions among sulfur species. By optimizing the active site exposure of FeS and designing a hierarchical porous and multichannel structure to ensure rapid migration of ions and electrons at the same time, the interlayer can effectively suppress the shuttle effect and enhance sulfur utilization. Thus, the Li-S battery presents excellent cycling stability and rate capability, namely, a reversible specific capacity of 560 mAh g-1 at 2.0 C over 500 cycles with a decay rate of 0.012% per cycle and a specific capacity of 597 mAh g-1 at a 5.0 C current rate. This study offers a promising strategy for designing the structure of an interlayer to achieve long-cycle stable Li-S batteries.