Confining Sulfur in Porous Carbon by Vapor Deposition to Achieve High-Performance Cathode for All-Solid-State Lithium-Sulfur Batteries

All-solid-state lithium-sulfur batteries (ASLBs) have the potential to achieve high energy density because of sulfur's high theoretical capacity (1672 mAh g-1) while alleviating persistent polysulfide shuttling inherent to lithium-sulfur batteries based on liquid organic electrolyte. However, the homogenization of sulfur, carbon, and solid electrolyte is a challenge to achieving high-performance cathodes for ASLBs. Herein, we demonstrate a promising sulfur-carbon composite with high sulfur content (71.4-83.3%) prepared using a sulfur vapor deposition (SVD) approach to show enhanced discharge specific capacities, rate performance, and cycling stability, outperforming conventional sulfur liquid deposition (SLD) and sulfur solid deposition (SSD) approaches. A higher discharge specific sulfur capacity of 1792.6 mAh g-1 has been achieved at 0.1C and 60 °C with improvement ascribed to smaller particle size and more homogeneous and deeply confined sulfur in sulfur-carbon composite, in contrast to 1619.2 and 1329.3 mAh g-1 for samples prepared by conventional SLD and SSD approaches, respectively.