Balancing Anodic Stability and Cathodic Kinetics in Practical Lithium‐Sulfur Batteries With Non‐fluorinated Weakly Solvating Solvents

Abstract The performance of lithium‐sulfur (Li‐S) batteries is crucially affected by the anodic stability of Li‐metal and cathodic conversion kinetics of sulfur‐carbon (S/C) composites. Herein, a weakly solvating electrolyte (WSE) with moderate lithium polysulfides (LiPSs) solubility, consisting of 1 M lithium bis(trifluoromethane sulfonyl) imide (LiTFSI) in non‐fluorinated solvent of cyclopentyl methyl ether (CPME) and 1,3‐dioxolane (DOL) additive, is employed in Li‐S batteries to simultaneously achieve high anodic stability and appropriate cathodic kinetics. This WSE exhibits a good capability of suppressing LiPSs shuttling by forming an anions‐dominated Li ⁺ solvation structure, effectively inducing a stable solid electrolyte interphase (SEI) to guarantee anodic stability of the Li‐metal anode. Additionally, the DOL additive in the WSE aids in forming a thin organic‐inorganic hybrid cathode electrolyte interphase (CEI) on the surface of S/Li ₂ S particles, which maintains good conversion kinetics and suppresses dead S/Li ₂ S growth in the S/C cathode. Consequently, Li‐S batteries with the WSE deliver a high initial capacity (≈1208 mAh g ⁻¹ ), a high average Coulombic efficiency (≈98.6%), and a high capacity retention rate (≈82.4%) over 200 cycles. Stable cycling performance over 100 cycles is also observed in the Li‐S pouch cell with the WSE even under harsh conditions.