Effect of the Dimensional Structure of Carbon-Based Materials on the Electrochemical Performance of All-Solid Lithium–Sulfur Batteries

All-solid-state lithium–sulfur batteries (ASSLSBs) based on sulfide solid-state electrolytes have attracted considerable attention due to their inherent immunity to the “shuttle effect,” superior safety characteristics, and high energy density. However, the insulating nature of sulfur (S8) necessitates the incorporation of conductive carbon-based carriers to enhance electrochemical performance. Notably, the dimensional structure and morphological characteristics of these carbon carriers significantly influence their physicochemical properties, thereby affecting the overall battery performance. In this study, we systematically investigated three representative carbon materials with distinct dimensionalities: zero-dimensional Ketjen Black (KB), one-dimensional carbon nanotubes (CNTs), and two-dimensional graphene (Gr) as sulfur hosts for ASSLSBs. Comprehensive electrochemical evaluations revealed that the S@CNT composite delivered the highest initial capacity exceeding 1200 mAh g–1 at 0.1C, significantly outperforming S@KB (>200 mAh g–1) and S@Gr (>700 mAh g–1). Furthermore, the S@CNT electrode demonstrated exceptional rate capability among the three materials. These findings elucidate the critical relationship between the dimensionality/morphology of carbon hosts and the electrochemical performance of ASSLSBs, offering valuable insights for the rational design of high-performance sulfur-based composite electrodes for next-generation solid-state batteries.