Fully carbonate-electrolyte-based high-energy-density Li–S batteries with solid-phase conversion

Abstract

Carbonate-electrolyte-based lithium–sulfur (Li–S) batteries with solid-phase conversion offer promising safety and scalability, but their reversible capacities are limited. In addition, large-format pouch cells are paving the way for large-scale production. This study demonstrates the in situ formation of a solid-electrolyte interphase (SEI) as a protective layer using vinylene carbonate (VC), highlighting its industrial adaptability. A high reversible capacity is achieved by the lithiated poly-VC SEI formed inside the cathode particles as a nanoscale ionic conduction path, along with the traditional surface protective layer. Furthermore, the severe dissolution of poly-VC is mitigated by LiF derived from fluorine ethylene carbonate as a co-solvent, enabling high rate performance and a long cycle life. A large 8 Ah pouch cell is successfully developed, which shows a high energy density of 400 Wh kg^–1 based on the cell weight. This work demonstrates the high performance of large-scale Li–S batteries with the in situ formation of a protective layer as a scalable technique for future applications.

Keywords

lithium–sulfur batteries / pouch cells / solid-electrolyte interphase