Modulating Solvation Structures via the Solvent Electronic Effects to Yield Fast‐Charging High‐Voltage Lithium‐Metal Batteries

ABSTRACT Breaking the long‐term trade‐off between fast‐charging kinetics, high‐voltage stability, and interfacial durability remains a core challenge in fabricating high‐energy‐density lithium‐metal batteries. Here, we propose a strategy for designing deep eutectic electrolytes by engineering ligand electronic structures to adjust Li + solvation microenvironments. This approach softens Li + solvation sheaths and synchronizes bulk‐phase ion transport with interfacial reaction kinetics. The resulting ternary electrolyte comprises lithium bis(trifluoromethanesulfonyl)imide, propane sultone, and 1‐propenyl‐1,3‐sultone in a molar ratio of 1:2:1 (TSE121), and it displays a wide electrochemical stability window (5.52 V), reduced Li + desolvation energy barrier, and high Li + transference number (0.82). Owing to its optimized solvation structure and programmed interfacial chemistry, TSE121 forms a stable gradient‐structured solid electrolyte interphase that can suppress lithium dendrite growth. Consequently, LiNi 0.8 Co 0.1 Mn 0.1 O 2 ||Li cells with TSE121 retain 83.6% of their capacities after 700 cycles at 4.5 V and 10C, while LiFePO 4 ||Li cells retain 84.7% of their capacities after 1500 cycles at 5C, and applicability in pouch cells is demonstrated. Thus, this study demonstrates that the engineering of the electronic structure of the solvent is an effective strategy for use in producing high‐energy, safe, fast‐charging lithium‐metal batteries.