Improvement of Redox Kinetics of Dendrite-Free Lithium–Sulfur Battery by Bidirectional Catalysis of Cationic Dual-Active Sites

Abstract

The practical application of lithium–sulfur batteries (LSBs) is hampered by the slow lithium polysulfide (LIPS) conversion kinetics and the uncontrollable anode-metal lithium dendrites. Herein, a three-dimensional cation dual-active-site eggshell structure compound (3DCS-FMO@C) was synthesized by soft template, ion exchange, and pyrolysis to modify the commercial separator. Experimental and theoretical analysis results showed that Mn2+ and Fe2+ sites in 3DCS-FMO@C can synergistically adsorb LIPSs, effectively regulate the bidirectional conversion dynamics of intermediate liquid-phase LIPSs and solid-phase lithium sulfide, and reduce the energy barrier of the reaction. The 3DCS-FMO@C-modified separator with high mechanical stability and no reduction in ion diffusion also had a lithiophilic central core that can homogenize the lithium-ion flow, thereby inhibiting the dendrite growth of lithium. Based on the above advantages, 3DCS-FMO@C-modified separator LSBs had better electrochemical performance, including an initial capacity of 1530 mAh g–1 at 0.1C and an ultralow decay rate of 0.029% for 1000 cycles at 0.5C. A high area capacity of 8.7 mAh cm–2 was achieved even with high sulfur loading and poor electrolyte. This work provided a basis for understanding the bidirectional catalysis for practical application in LSBs and simultaneously solved the problem of lithium dendrites.

Layered CoMoS3.13@NCNTs with a Rod-Shaped Skeleton as the Cathode of Lithium–Sulfur Batteries

“…Battery optimization to solve the above questions has been achieved by improving theoretical and experimental steps; such optimization efforts include improving the cathode sulfur host material, 13 lithium anodes, 14 and electrolytes 15 and using modified diaphragms. 16 Considerable research has been devoted to carbon materials, which are currently used in a wide range of applications as sulfur-hosting materials for anodes. These carbon materials include carbon nanotubes, 17 graphene, 18,19 and ordered mesoporous carbon.…”

Polyoxometalates@Metal‐Organic Frameworks Derived Bimetallic Co/Mo2C Nanoparticles Embedded in Carbon Nanotube‐Interwoven Hierarchically Porous Carbon Polyhedron Composite as a High‐Efficiency Electrocatalyst for Al–S Batteries

“…[21] In contrast, S is a conversiontype material that interconverts with polysulfides in non-aqueous electrolytes offering high theoretical specific capacity (1675 mAh g −1 ), low cost, and environmental friendliness. [22][23][24][25][26][27][28][29] Despite being promising candidates for next-generation rechargeable secondary batteries, Al-S battery (ASB) has not been extensively studied.…”