Synthesis and Investigation of the Effects of SnS as an Additive for Sulfur in Lithium-Sulfur Batteries

Lithium–sulfur (Li–S) batteries are recognized for their outstanding theoretical energy density, positioning them as potential candidates for future energy storage technologies. Despite this advantage, their commercial development is constrained by significant obstacles, notably the inherently low as a consequence of sulfur's limited conductivity and the transport of lithium polysulfides into the electrolyte, which leads to active material loss and capacity deterioration over cycling. To address these issues, this study introduces tin sulfide (SnS), synthesized through a hydrothermal route, as a functional additive in sulfur-based cathodes for polymer-based solid-state Li–S batteries. A systematic evaluation of various SnS-to-sulfur ratios revealed that the 1:4 ratio delivered the most improved electrochemical behavior. The optimized cell achieved a discharge capacity reaching approximately 1050 mAh·g⁻¹ after 20 cycles and maintained a Coulombic efficiency exceeding 80% throughout the testing period. These findings demonstrate that incorporating SnS not only improves the electrical conductivity but also stabilizes sulfur conversion reactions, offering an effective approach toward the development of high-performance solid-state Li–S batteries.