Taming Solvent-Solute Interaction Accelerates Interfacial Kinetics in Low-Temperature Lithium Metal Batteries.

Lithium (Li) metal batteries promise energy density beyond 400 Wh kg -1 , while their practical operation at an extreme temperature below -30°C suffers severe capacity deterioration. Such battery failure highly relates to the remarkably increased kinetic barrier of interfacial processes, including interfacial desolvation, ion transportation, and charge transfer. In this contribution, the interfacial kinetics in three prototypical electrolytes are quantitatively probed by three-electrode electrochemical techniques and molecular dynamics simulations. Desolvation as the limiting step of interfacial processes is validated to dominate the cell impedance and capacity at low temperature. 1,3-dioxolane-based electrolyte with tamed solvent-solute interaction facilitates fast desolvation, enabling the practical Li | LiNi 0.5 Co 0.2 Mn 0.3 O 2 cells at -40°C to retain 66% retention of room-temperature capacity and withstand remarkably fast charging rate (0.3 C). The barrier of desolvation dictated by solvent-solute interaction environments has been quantitatively uncovered. Regulating the solvent-solute interaction by low-affinity solvents emerges as a promising solution to low-temperature batteries. This article is protected by copyright. All rights reserved.