Solvent-Anchored Electrolyte Enables Stable Operation of 600 Wh Kg^-1 Lithium Metal Pouch Cells Under High-Voltage.

Abstract

Lithium metal batteries (LMBs) are regarded as promising candidates for next-generation high-energy-density storage systems. However, their practical application is severely hindered by rapid performance degradation under high-voltage and lean-electrolyte conditions. Constructing an anion-enriched solvation structure to generate an inorganic-rich solid electrolyte interphase (SEI) is critical for ensuring the stable operation of lithium metal batteries. Herein, a novel anion-enrichment strategy is proposed by introducing a rigid cationic species (F-TEDA⁺) as a molecular anchoring additive to design a solvent-anchored electrolyte (SAE). F-TEDA⁺ anchors solvent molecules via strong ion-dipole interactions, enabling the formation of an anion-enriched solvation structure comparable to that of high-concentration electrolytes, even at an ultralow additive dosage and conventional salt concentration. Notably, the rigid molecular framework of F-TEDA⁺ endows it with excellent electrochemical stability, allowing persistent regulation of the solvation structure during long-term cycling. As a result, a 14.2 Ah Li‖Ni95 pouch cell reaches 615.3 Wh kg^-1 and retains 91.4% capacity after 70 cycles at 4.5 V. This work proposes a nonconsumable solvation regulation strategy, providing a new avenue for the development of high-voltage, high-energy-density lithium metal batteries.