Multiple Covalent Triazine Frameworks with Strong Polysulfide Chemisorption for Enhanced Lithium‐Sulfur Batteries

Abstract

Abstract Endowed with high theoretical energy density, low cost, and environmental friendliness, lithium‐sulfur batteries have a promising future in energy storage. The volume expansion of the sulfur cathode, shuttle effects, and the insulating nature of polysulfide result in poor cycling stability and limit practical applications of lithium‐sulfur batteries. In this work, these matters are relieved by physically and chemically restricting sulfur species in highly fluorinated sulfur‐rich multiple covalent triazine frameworks synthesized through nucleophilic aromatic substitution reaction chemistry. It exhibits a specific capacity of 681 mAh g −1 and capacity retention of 62.6 % after 400 cycles, indicating a 0.09 % degradation per cycle. The superiority in cycle performance is attributed to the homogeneous distribution of sulfur, covalent bonding of sulfur, and affinity for polysulfide of triazine rings.