Single-phase gradient-solvation-electrolyte-stabilized Li metal batteries

Ether-based electrolytes have shown great success for lithium metal electrodes1,2,3,4,5. However, during the charging process of high-voltage full cells, the desolvation of solvents and anions to accommodate Li ions released from the positive electrode exacerbates oxidative decomposition of the electrolyte6. In addition, the continuous consumption of components over extended cycling substantially alters the solvation structure, resulting in deteriorating redox stability. Here we incorporate a targeted ligand anti-solvent (TLAS) into an anion-rich ether-based electrolyte. The TLAS barely participates in the solvation of Li+ owing to its relatively weaker association ability in a static state. Under the strong electric field of high-voltage full cells, the orientation and distribution of the TLAS undergo substantial transformation, with coordination ability activated on the positive electrode surface. The TLAS-mediated dynamic solvation behaviour bypasses the inherent decoordination and recoordination of solvents and anions on the positive electrode in conventional electrolyte systems, thus minimizing electrolyte reconstruction and interphase deterioration. Leveraging this gradient solvation electrolyte, we develop a 450 Wh kg−1 lithium metal pouch cell that achieves a long cycle life exceeding 750 cycles (80% capacity retention). Furthermore, we validated a lithium metal pouch cell with a high energy density of 605 Wh kg−1, which achieves 150 cycles with 96% capacity retention. This gradient solvation strategy provides a feasible pathway of electrolyte engineering for metal-ion batteries.