Building Lithium-Polycarbonsulfide Batteries with High Energy Density and Long Cycling Life

The polysulfide shuttling and restricted kinetics of existing sulfur cathodes of lithium–sulfur batteries need to be tackled. Herein, we synthesized a polycarbonsulfide active material with an atomically assembled π-conjugated 3D conductive matrix via the self-polymerization of carbon disulfide (CS2) monomers. The as-synthesized polycarbonsulfide features oligo-S heterocycles assembled to conjugated conductive carbon chains. The coupled lithium-polycarbonsulfide battery delivered a high capacity of 724.5 mAh g–1 at 1.0 C (corresponding to 827.3 Wh kg–1) with an ultralow capacity decay rate of 0.032% per cycle, as well as high-rate capability of 499.6 mAh g–1 at 3.0 C. Multiple ex situ spectroscopic analyses revealed that the robust π-conjugated conductive polymeric matrix was well preserved during repeated battery operation, which efficiently tethered the discharge products to greatly restrict the shuttling effect.