Expediting Polysulfide Anchoring by Fe 3 O 4 /Reduced Graphene Oxide Composite for High‐Performance Lithium‐Sulfur Batteries

The inherent low conductivity of sulfur, sluggish redox kinetics, and the challenge of maximizing active material utilization are the bottlenecks for practical implementation in lithium‐sulfur (Li−S) battery technology. Herein, a low‐cost Fe 3 O 4 ‐rGO that serves as both a sulfur host matrix and an electrocatalytic interlayer in a Li−S battery has been synthesized. With the merit of high specific surface area, Fe 3 O 4 ‐rGO offers high sulfur loading (80 wt. %) and sufficient space to accommodate sulfur volume expansion during the redox reaction. The symmetric cell experiment demonstrated that Fe 3 O 4 in the rGO structure promotes the lithium polysulfide (LPS) redox conversion. The Li−S battery is constructed using the Fe 3 O 4 ‐rGO@S as the cathode and Fe 3 O 4 ‐rGO as the interlayer, demonstrating an impressive specific capacity of 1258 mAh g −1 at 0.1 C and the battery retained 76 % of its capacity after 400 cycles at 0.5 C. This study also explores the confinement of LPS on the Fe 3 O 4 ‐rGO@S_Fe 3 O 4 ‐rGO cathode and interfacial redox kinetics by dynamic electrochemical impedance spectroscopy. This work presents a cost‐effective method for improving the catalytic conversion of lithium polysulfides, which can contribute to the development of high‐performance lithium‐sulfur batteries.