Bifunctional ligand-bridged electrolyte enables high-capacity and high-energy 600 Wh kg^-1 lithium-metal battery pouch cells.

Abstract

Lithium metal batteries offer a pathway toward next-generation energy storage due to their high specific energy. However, their implementation remains challenging, particularly under lean electrolyte conditions, where unstable interfaces and inefficient ion transport severely limit cycling stability. Here, we show a bifunctional ligand-bridged electrolyte by integrating ethyl difluoroacetate into a lithium nitrate/triethyl phosphate matrix. Incorporating ethyl difluoroacetate as a dynamic bridging agent drives the formation of interconnected ionic aggregates through synergistic H^δ+ - O^δ- hydrogen bonding with anions and coordination interactions with Li⁺, thereby accelerating interfacial kinetics and suppressing parasitic reactions. The electrolyte further enables weakly coordinating solvents to engage in the solvation sheath via non-classical hydrogen bonding, facilitating the formation of a robust, inorganic-rich solid electrolyte interphase. This design enables the realization of high-capacity (14 Ah) Li‖Ni95 pouch cells, which achieve a specific energy of 606.8 Wh kg^-1 while maintaining 92.9% capacity retention after 75 cycles at rates of 0.1 C/0.2 C. These findings demonstrate a viable electrolyte strategy for enabling high-performance lithium metal batteries under practical conditions.