Solvent-Type Salt with Dynamic Solvation Reconfiguration Enables Fast-Charging Lithium Metal Batteries

The solvation structure of Li + critically governs charge-transfer kinetics and interfacial chemistry in lithium metal batteries (LMBs), yet achieving desired modulation is highly challenging due to the intertwined Li + -anion and solvent interactions. This complexity becomes particularly critical under fast-charging conditions, where sluggish Li + desolvation and unstable interphases severely limit electrochemical kinetics. Here, we report a “solvent-type” and molecularly engineered lithium organofluorinated aluminate salt (LiFA), with a polyether chain adjacent to the aluminate center, allowing the salt to encapsulate Li + into its solvation domain, while the electron-deficient aluminate core and bulky fluorinated pendants achieve delocalization of charge and promote Li + dissociation. In-depth experimental and molecular dynamics analyses reveal that such salt design could enable dynamic reconfiguration of Li + solvation structures and balance between contact ion pairs and solvent-separated ion pairs, substantially accelerating charge-transfer and stabilizing the interfaces. This “solvent-type” salt strategy offers a dynamic solvation regulation approach to reconfigure the Li + -anion coordination environment and synergistically enhance desolvation kinetics from interfacial stability, shedding light on electrolyte discovery toward fast-charging and durable LMBs.