Synergistic Compound Additives for High‐Performance Lithium–Sulfur Batteries

Abstract Lithium–sulfur (Li–S) batteries, with theoretical energy densities exceeding 2600 Wh kg −1 , are poised to revolutionize energy storage. However, their practical viability hinges on resolving two critical challenges: uncontrolled lithium dendrite growth at the anode and polysulfide shuttling at the sulfur cathode. Here, a compound additive integrating lithium nitrate (LiNO 3 ), sodium saccharin (SAC), and octaphenyl polyoxyethylene (OP‐10) is proposed to construct an electrolyte for Li–S battery. With the compound additive added, the as‐prepared electrolyte is capable of evolving a robust solid electrolyte interphase (SEI) with refined morphology while suppressing polysulfide reactivity. The synergistic effects of this additive enable Li|Li symmetric cells to achieve unprecedented cycling stability (>1400 h at 1 mA cm −2 and 3 mAh cm −2 ) and Li–S full cells with high sulfur loading (4.12 mg cm −2 ) to retain 2.72 mAh cm −2 after 150 cycles. This work underscores the importance of dual‐electrode stabilization in electrolyte design, offering a scalable strategy for high‐energy‐density Li–S batteries and related systems plagued by dendrites and shuttle effects. This study highlights the effectiveness of synergistic electrolyte engineering in suppressing lithium dendrites and polysulfide shuttling, providing new insights for the development of high‐performance Li–S batteries and other energy storage systems facing similar challenges.