Li‐Rich Organosulfur Cathode with Boosted Kinetics for High‐Energy Lithium‐Sulfur Batteries

Abstract

Organosulfur materials containing sulfur–sulfur bonds are an emerging class of high‐capacity cathodes for lithium storage. However, it remains a great challenge to achieve rapid conversion reaction kinetics at practical testing conditions of high cathode mass loading and low electrolyte utilization. In this study, a Li‐rich pyrolyzed polyacrylonitrile/selenium disulfide (pPAN/Se2S3) composite cathode is synthesized by deep lithiation to address the above challenges. The Li‐rich molecular structure significantly boosts the lithium storage kinetics by accelerating lithium diffusivity and improving electronic conductivity. Even under practical test conditions requiring a lean electrolyte (Electrolyte/sulfur ratio of 4.1 μL mg−1) and high loading (7 mg cm−2 of pPAN/Se2S3), DL‐pPAN/Se2S3 exhibits a specific capacity of 558 mAh g−1, maintaining 484 mAh g−1 at the 100th cycle with an average Coulombic efficiency of near 100%. Moreover, it provides (electro)chemically stable Li resources to offset Li consumption over charge–discharge cycles. As a result the as‐fabricated anode‐free cell shows a superior cycling stability with 90% retention of the initial capacity over 45 cycles. This study provides a novel approach for fabricating high‐energy and stable Li–SPAN cells.