Solvation-interphase synergistic regulation empowering high-temperature and fast-charging lithium metal batteries

Abstract

Lithium metal batteries (LMBs) have emerged as pivotal energy storage solutions for electric vehicles and portable electronics. However, their operation under extreme conditions (high-temperature and fast-charging conditions) faces significant challenges, including accelerated electrolyte decomposition, interfacial instability, and potential thermal runaway risks. To address these challenges, we present a solvation-interphase synergistic regulation strategy using 2-fluorobenzenesulfonamide (2-FBS) as a multifunctional electrolyte additive. The 2-FBS molecule effectively modulates the Li⁺ solvation structure by reducing the coordination of ethylene carbonate (EC) solvent. This transformation suppresses EC-induced parasitic reactions while scavenging superoxide radicals, thereby mitigating gas evolution at electrode interfaces. Upon preferential decomposition, 2-FBS further promotes the formation of a robust LiF-Li₃N-Li₂S-rich interphase with exceptional mechanical strength (Young’s modulus: 39.4 GPa). This inorganic-rich hybrid interphase simultaneously enables dendrite-free lithium plating and enhances cathode thermal stability. Consequently, 2-FBS-modified electrolyte empowers LiCoO₂//Li cells to deliver 82.8 % capacity retention after 800 cycles at 55 °C and sustain 81.2 % capacity retention after 1500 cycles at 4 C. Moreover, practical validation through nail penetration tests confirms the effectiveness of the electrolyte in preventing thermal propagation in fully charged pouch cells. This work establishes a paradigm for enabling reliable battery operation under extreme conditions through synergistic solvation and interphase engineering.