Anchoring Polysulfides and Accelerating Redox Reaction Enabled by Fe‐Based Compounds in Lithium–Sulfur Batteries

Abstract

The synergetic mechanism of chemisorption and catalysis play an important role in developing high‐performance lithium–sulfur (Li–S) batteries. Herein, a 3D lather‐like porous carbon framework containing Fe‐based compounds (including Fe3C, Fe3O4, and Fe2O3), named FeCFeOC, is designed as the sulfur host and the interlayer on separator. Due to the strong chemisorption and catalytic ability of FeCFeOC composite, the soluble lithium polysulfides (LiPSs) are first adsorbed and anchored on the surface of the FeCFeOC composite and then are catalyzed to accelerate their conversion reaction. In addition, the FexOy in Fe‐based compounds can spontaneously react with LiPSs to form magnetic FeSx species with a larger size, further blocking the penetration of LiPSs cross the separator. As a result, the assembled Li–S cells show excellent long‐term stability (748 mAh g−1 over 500 cycles at 1.0 C, and ≈0.036% decay per cycle for 1000 cycles at 3.0 C), a superb rate capability with 659 mAh g−1 at 5.0 C, and lower electrochemical polarization. This work introduces a feasible strategy to anchor and accelerate the conversion of LiPSs by designing the multifunctional Fe‐based compounds with high chemisorption and catalytic activity, which advances the large‐scale application of high‐performance Li–S batteries.

Efficient Anchoring of Polysulfides Based on Self-Assembled Ti3C2Tx Nanosheet-Connected Hollow Co(OH)2 Nanotubes for Lithium–Sulfur Batteries

“…36 With the passage of time, new peaks gradually appeared at 26.5−27.5°belonging to Li 2 S, and the peaks of S became weaker to detect. No other lithium polysulfide peaks were observed, indicating the perfect conversion from S to Li 2 S. 37 At the same time, there is no visible change observed in the signals located at 19.1°that 6c) of the Co(OH) 2 @Ti 3 C 2 T x @S demonstrate a typical process from the S 8 to Li 2 S, which is in good accordance with the previous reports. 15,38,39 At the high potential (2.8 V), the peaks at 145, 215, and 465 cm −1 belong to the S substance.…”

Hypercrosslinked Polymerization Enabled N‐Doped Carbon Confined Fe2O3 Facilitating Li Polysulfides Interface Conversion for Li–S Batteries

“…embedded in 3D lather‐like porous carbon framework as the sulfur host and the coating layer on polypropylene separator. [ 11 ] Although the Fe‐based Li–S cells showed excellent long‐term stability over 500 cycles at 1.0 C, the modified separator would impair the volume energy density. Hence, due to the lack of reasonable design between the conductive carbon and these catalysts, the composite cathodes often showed the undesirable anchoring and conversion ability of LiPSs, especially, at high sulfur content (>80%) and sulfur loading (>5 mg cm −2 ) with lean E/S ratio condition (<10 µL mg −1 ).…”

Reduced Graphene Oxide-Coated Zinc–Cobalt Oxide Nanosheet Arrays with N-Doped Carbon Anchored on Carbon Cloths as Cathode Materials for High-Sulfur-Loading Li–S Batteries

“…In addition, the Coulomb efficiency remained almost 100% during the high-load cycle, which meant that most of the LiPSs were successfully fixed to the cathode during the electrochemical reaction. Under high loading (8.2 mg cm –2 ), the rGO-S/ZnCo 2 O 4 @NC/CC cathode of Li–S batteries still has excellent specific capacity and cycle performance, which are higher than many previously reported cathodes and have been summarized in Figure d and Table S2. − …”