Building Lithium-Polycarbonsulfide Batteries with High Energy Density and Long Cycling Life
Anyang Tao, Kaiqiang Zhang, Xingkai Ma, Xinmei Song, Junchuan Liang, Yaoda Wang, Yuzhu Liu, Jin Li, Zuoxiu Tie, Zhong Jin
Abstract
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.