《Bifunctional Fluorinated Anthraquinone Additive for Improving Kinetics and Interfacial Chemistry in Rechargeable Li-S Batteries》

The uncontrolled deposition of lithium anodes and the severe shuttle effect of polysulfides hinder the commercial application of lithium-sulfur batteries. In this work, we propose a bifunctional electrolyte additive 1,4-difluoroanthraquinone (DFAQ) for regulating the lithium anode interface and accelerating sulfur-redox kinetics. DFAQ is conducive to the formation of stable and smooth lithium fluoride-rich organic-inorganic composite solid electrolyte interphase (SEI), achieving excellent reversible lithium intercalation and delition behavior, inhibiting dendrite growth and shielding lithium anode from side reactions with polysulfides. More importantly, DFAQ can also be used as a redox medium to catalyze the conversion of polysulfides by oxygen radicals. Therefore, lithium-sulfur batteries with DFAQ exert ultra-high discharge specific capacity, high rate performance and excellent long-cycle stability (1693.4 mAh g-1, 0.5C cycle 700 turns). At the same time, under the practical conditions of high sulfur loading (5.8 mgS cm-2), ultra-thin lithium metal (50 μm) and low E/S ratio (5.0 μL/mgS), the battery showed high reversible surface capacity (9.6 mAh cm-2) at 0.1C and stable cycle for 80 cycles. This work provides a new strategy for the construction of practical high-energy-density lithium-sulfur batteries.

https://pubs.acs.org/doi/abs/10.1021/acsaem.2c03306