Sulfur/Graphite Composite Material for All-Solid-State Lithium-Sulfur Batteries: A Cost-Effective and High-Performance Cathode Solution for Next-Generation Energy Storage

Lithium-sulfur batteries (LSBs) have garnered considerable interest as a highly potential energy storage technology for the next generation, offering a theoretical energy density up to 2500 Wh/kg and a high specific capacity of 1675 mAh/g. Their appeal is further strengthened by the use of cost-effective raw materials (around $180 per ton) and their environmentally friendly characteristics. However, challenges such as sulfur's exhibiting intrinsically low electrical conductivity and undergoing substantial volumetric expansion during charge-discharge processes., and the polysulfide shuttle phenomenon impede their commercial viability. To address these issues, this work developed sulfur/graphite composites with a 6:4 mass ratio via ball milling, employed as cathodes in all-solid-state lithium-sulfur batteries (ASSLSBs). The incorporation of graphite enhanced electrical conductivity and provided a porous structure that improved sulfur utilization and suppressed polysulfide migration. Moreover, the incorporation of graphite facilitated improved electron and ion transport and effectively inhibited the formation of insulating lithium sulfide layers on the cathode surface. The composite cathode demonstrated a preliminary discharge capacity of 448 mAh/g and a Coulombic efficiency of 89.82%, as revealed by electrochemical measurements. After 30 charge-discharge cycles, the capacity remained stable at 402 mAh/g, with the Coulombic efficiency reaching 100%, indicating a capacity retention of approximately 90% relative to the initial cycle.