Nano-Confinement of Insulating Sulfur in the Cathode Composite of All-Solid-State Li-S Batteries Using Flexible Carbon Materials with Large Pore Volumes.

Durable nanostructured cathode materials for efficient all-solid-state Li-S batteries were prepared using a conductive single-walled 3D graphene with a large pore volume as the cathode support material. At high loadings of the active material (50-60 wt %), microscale phase segregation was observed with a conventional cathode support material during the charging/discharging processes but this was suppressed by the confinement of insulating sulfur into the mesopores of the elastic and flexible nanoporous graphene with a large pore volume of 5.3 mL g-1. As such, durable three-phase contact was achieved among the solid electrolyte, insulating sulfur, and the electrically conductive carbon. Consequently, the electrochemical performances of the assembled all-solid-state batteries were significantly improved and feasible under the harsh conditions of operation at 353 K, and improved cycling stability as well as the highest specific capacity of 716 mA h per gram of cathode (4.6 mA h cm-2, 0.2 C) was achieved with high sulfur loading (50 wt %).