Lithium Tritelluride as an Electrolyte Additive for Stabilizing Lithium Deposition and Enhancing Sulfur Utilization in Anode‐Free Lithium–Sulfur Batteries

Abstract Despite the potential to become the next‐generation energy storage technology, practical lithium–sulfur (Li–S) batteries are still plagued by the poor cyclability of the lithium‐metal anode and sluggish conversion kinetics of S species. In this study, lithium tritelluride (LiTe 3 ), synthesized with a simple one‐step process, is introduced as a novel electrolyte additive for Li–S batteries. LiTe 3 quickly reacts with lithium polysulfides and functions as a redox mediator to greatly improve the cathode kinetics and the utilization of active materials in the cathode. Moreover, the formation of a Li 2 TeS 3 /Li 2 Te‐enriched interphase layer on the anode surface enhances ionic transport and stabilizes Li deposition. By regulating the chemistry on both the anode and cathode sides, this additive enables a stable operation of anode‐free Li–S batteries with only 0.1 m concentration in conventional ether‐based electrolytes. The cell with the LiTe 3 additive retains 71% of the initial capacity after 100 cycles, while the control cell retains only 23%. More importantly, with high utilization of Te, the additive enables significantly better cyclability of anode‐free pouch full‐cells under lean electrolyte conditions.