Customized Solvation Structures for Long-Term Stable Lithium Metal Batteries

Lithium metal batteries (LMBs) suffer from severe lithium dendrite growth and side reactions in conventional carbonate electrolytes, which are characterized by low coulombic efficiency and poor cycling stability, and electrolyte engineering is an effective method for increasing the reversibility of lithium anodes. Herein, the solubility of lithium nitrate (LiNO₃), which is almost insoluble in carbonate electrolyte, is improved by adding zinc trifluoroacetate (Zn(TFA)₂), and a competitive solvation structure is constructed, forming an anion-enriched Li⁺ solvation structure, which is conducive to the formation of stable SEI and effectively inhibits adverse side reactions. The lithium metal anode exhibits uniform lithium deposition and extended cycle life, with high reversibility over plating/stripping for 640 h. Furthermore, the Li||LFP full cell with the upgraded carbonate electrolyte can operate steadily for over 300 cycles at 1 C, and the compatibility of the lithium anode with the high-voltage NCM811 cathode are also significantly improved. This work provides a feasible strategy for dependable interfacial chemistry of lithium metal anodes.