Tailoring anion-enriched and fluoroethylene carbonate coordinated weak solvation structure for interfacial-stable...

The development of practical lithium (Li) metal battery (LMB) is severely restricted by the poor stability of electrode-electrolyte interfaces (EEIs) and sluggish interfacial kinetics. Modulating Li-ion solvation structure is critical for addressing this issue, but remains challenging. Herein, we propose a novel strategy of incorporating multiple anions and functional solvent to tailor a unique anion-enriched and fluoroethylene carbonate (FEC) coordinated weak solvation structure for interfacial-stable high-performance LMBs. Theoretical calculations and experimental results indicate that the first Li-ion solvation sheath is dominated by multiple anions and FEC molecules, leading to a largely diminished coordination of Li⁺-solvents and an accelerated interfacial dynamics. Simultaneously, inorganic-rich robust EEIs are further constructed via the preferential redox decomposition of the solvated anions and FEC molecules, achieving a remarkable interfacial stability and dendrite-free Li plating/stripping behavior. Consequently, the symmetric Li||Li cells realize an ultra-long stable cycle of 5400 h at 2 mAh cm^-2, and the Li||LiFePO₄ (LFP) full cells demonstrate an excellent rate and cycling performance even under high LFP-loading, relatively low negative/positive capacity ratio (N/P) and less electrolyte usage. Our findings reveal a facile proposal to precisely tailor weak Li-ion solvation structure by integrating anion chemistry and functional solvent, paving the way for advanced electrolyte design and high-performance LMBs development.