Customization Nanoscale Interfacial Solvation Structure for Low Temperature Lithium Metal Batteries

Abstract

Regulating the nanoscale interfacial solvation structure involving the ion coordination in the electric double layer is of significant importance to the construction of stable and rapid ion-transport solid-electrolyte interphase for revolutionary lithium metal batteries (LMBs) operated under low temperature serving conditions. Herein, an efficient strategy of using PMETAC polymer brush to regulate nanoscale interfacial solvation structure is proposed, which is universal to different electrolyte chemistry and service temperature. The combined attenuated total reflection analysis and theoretical simulations reveal the unique interfacial solvation structure and the underlying synergistic mechanism. Due to the electrostatic interaction between the quaternary amino nitrogen of polymer brushes and electrolyte anions, as well as the unique steric hindrance effect originated from the polymer brushes, the solvent molecules are excluded from the first inner solvation shell and more anions enter into the electric double layer to participate in the Li ion coordination, thus prompting the formation of stable inorganic-rich SEI with favorable ion-transport. With the unique nanoscale interfacial solvation structure, the assembled LMBs achieve stable operation at both room temperature for over 1.7 years and a low temperature of -20 C. More exciting, the strategy can support the industrial manufacturing of Ah-level anode-free Li metal pouch cells. This work reveals the importance of regulating nanoscale interfacial solvation structure, promoting the realistic applications of high-energy LMBs operated under various service conditions.