Entropy‐Driven Electrolyte Design for Lithium Metal Batteries: Achieving Interfacial Stability With Fluorinated Fullerene Nanoparticle Additives

Abstract

ABSTRACT Lithium metal batteries are highly attractive for next‐generation high‐energy‐density storage, and ether‐based electrolytes such as LiFSI/DME are particularly promising for high‐rate operation because of their low viscosity, high ionic conductivity, and favorable compatibility with Li metal. However, current electrolyte optimization strategies still rely mainly on small‐molecule additives that regulate bulk solvation or the primary Li + solvation sheath, whereas entropy‐driven modulation of the interfacial solvation environment by large molecular additives remains largely unexplored. Herein, fluorinated fullerene C 60 F 30 (FF) is introduced as a nanoparticle additive to create a dynamically disordered interface that enhances configurational entropy without sacrificing Li + diffusivity, while accelerating Li + desolvation and transport. Meanwhile, FF cooperates with FSI − ‐derived species to build a robust fluorine‐rich SEI, suppressing dendrite growth and parasitic reactions. As a result, Li||Li symmetric cells cycle stably for 1500 h, while high‐loading Li||LiFePO 4 cells retain 96.0% capacity after 500 cycles at 2C and 95.9% after 1000 cycles at 10C. Moreover, pouch cells and high‐loading Li||NCM811 cells further verify the practical promise of the FF‐enabled electrolyte for high‐rate, long‐cycling LMBs.