Conducting Carbon Rich Graphitic Carbon Nitride Nanosheets with Attached Nano Sulfur Copolymer as High Capacity Cathode for Long-Lifespan Lithium-Sulfur Battery

Abstract

A mesoporous, conducting, high specific surface area, carbon-rich graphitic carbon nitride (GCN) nanosheets host covered by nano sulfur copolymer has been reported as a cathode material that shows high capacity along with long cyclability for rechargeable lithium-sulfur batteries (LiSBs). The thermal pyrolysis technique has been used for carbon-rich GCN sheets synthesis, and the chemical deposition approach has been used to attach surface nanoparticles to the sheets. Further, to improve the binding of nano sulfur with host material, copolymerization of nano sulfur is carried out with help of 1,3-diethynylbenzene (DEB) monomer through the solution route. The sulfur nanoparticles are loaded on conducting carbon-rich GCN framework for fast electro kinematics and further copolymerization of sulfur nanoparticles is done to prevent the dissolution of the active material (sulfur) into the electrolyte during the charging/discharging for high capacity and long cycle life rechargeable LiSBs cathode preparation. The synthesized composite with high sulfur loading (∼76 wt.% of composite cathode material) as cathode shows an initial discharge capacity of ∼1380 mAh g−1 at 0.1 C and a good discharge capacity of ∼700 mAh g−1 after 1000 cycles at 1 C with ultra-low-capacity fading ∼0.016 % of the initial capacity in each cycle. © 2022 Wiley-VCH GmbH.